Mid-Atlantic Pocket Guide to Water Garden Species

Introduction

Using native species in water gardening helps to diversify the ecosystem and provide habitat, food, and resources critically needed by native insects, birds, small mammals, pollinators, and other wildlife. This guide provides details about each native alternative such as growth height, soil and sun needs, hardiness zones, and additional information like ecosystem benefits, various tolerances, and more.  

Why Choose Native? 

Since the colonial era, there has been a long tradition of introducing non-native, exotic plants into water gardens. Many of these plants have highly manipulated characteristics that focus on appearance and novelty, rather than function. They are often not well-adapted to local conditions and do not play a healthy role in regional ecology. Non-native plants have limited ecological functions and contribute to habitat degradation because they fail to provide necessary support to the interconnected network of native species, from essential microbial life to beneficial insects, birds, and wildlife.

Native plants, or plants that have developed regionally without human intervention, have evolved to be well-adapted to local conditions. The genetic variability of naturally propagated native plants often makes them more resilient and survivable in unfavorable conditions, such as extreme heat or cold, disease, or pest pressure. They also tend to have a deeper, more diverse root architecture, which not only helps stabilize soils and trap stormwater and runoff pollutants but also contributes to survivability during drought. Most importantly, native plants have co-evolved with other Pennsylvania native species and provide nourishing food, appropriate nesting sites, and other ecosystem functions that support life. Large and small-scale habitat destruction and fragmentation have resulted in significant declines in native species of all types. Choosing native helps buffer against changing climate and plummeting biodiversity, and the tools and resources are readily available.

Integrating more native plants into existing water gardens starts by considering more than just blooms. Native plants should be selected not just for beauty but also for the benefits they contribute to site conditions and increased ecological functions. This includes offering multiple types of nectar and seeds at different times of the year, capturing pollutants, improving soil infiltration, providing nesting materials, creating sheltered spaces, increasing genetic diversity, and more. Native plants can easily be added to containers, currently unplanted spaces, or used to replace areas of low ecological value.

The plants suggested are known to be native to Pennsylvania and the Mid-Atlantic region. They are suggestions only, and there are other plants you can select that may better suit your garden site. Before selecting plants for your water garden, or any landscaping project, research the plants you want to use to be sure they suit the site and meet your aesthetic criteria.

Visit the Habittatitude™ website for invasive species information specific to water gardens and aquaria.

Water Gardens

A water garden is fundamentally an outdoor aquarium. The gardener needs to manage the pH, nutrients, and organisms introduced into the system. Just because a plant or animal is invasive doesn't mean it can't be ordered and delivered to your door or purchased locally. Unwelcome hitchhikers may also accompany your purchase. Plants and animals known to be invasive or prohibited in the state are often part of plant orders in the water or plant medium or used for packing.

Prevent Introducing Hitchhikers

• Rinse plants in a light-colored bucket of clear tap water until clean
• Dispose of any packing materials or water only after disinfection

Watch for animals or other plant fragments. If it seems likely that the plant has hitchhikers, you can clean emergent types of plants such as arrowhead (Saggitaria spp.). Dip the plant in a 10% chlorine solution, swish it around, and shake it off. Rinse in tap water after 30 seconds. This should not be used on submerged plants like Elodea (Elodea canadensis).

Any hardy non-native plant or animal species may become the next problematic invasive species that can clog our waterways and damage wildlife habitat. In addition, many closely related (same genus) plants can hybridize with the native species, often passing on aggressive traits. Our suggestion is to use native plants whenever possible.

When selecting plants, consider using species native to the region or non-invasive exotic plants. Never use any invasive plant unless it is well outside its hardiness zone, and even then with caution. The USDA plant hardiness zone map is the standard by which gardeners can determine which plants are most likely to thrive at a location. Pennsylvania ranges in hardiness zones from 5a in north central to 7b in southeastern and southwestern regions. Choose a reputable nursery, ask if the vendor is aware of regional or federal restrictions and verify the scientific names are correct. Common names may be used for several different species, not all of which are harmless.

Tips for Water Gardening with Native Plants & Animals

Water gardening is a popular hobby and one of the fastest-growing areas of the aquarium trade. Water gardens are beautiful and promote feelings of peace and serenity, but they can also create accidental routes of non-native and invasive species introductions. Maintaining water gardens responsibly helps property owners maintain the health of the surrounding ecosystem while still enjoying a beloved hobby. Choosing native species for water gardens can promote local ecosystem diversity without introducing ornamentals or potentially invasive species to the watershed. 

Invasive species can move out of a water garden in a variety of ways, including direct release by the property owner, escape into a natural waterway after an extreme weather event, including flooding and high winds, or improper disposal of unwanted plant material. The following tips will help construct and maintain a water garden so that these unintended consequences can be avoided.

Construction of a New Water Garden

Choose a location away from natural waterways and flood-prone areas to ensure that plants and animals from the water garden cannot escape during extreme weather events. 

Considerations for Adding Plants

Purchase from a licensed nursery. Choose species that are native to the region or, at a minimum, not invasive.  Take time to review the latest Pennsylvania Noxious Weeds, Federal Noxious Weeds, and Pennsylvania Banned Species lists.  Plants and animals on these lists should never be purchased or transported due to their extremely invasive nature. Any purchased plants should be rinsed over a trash bin before adding them to the water garden to prevent the introduction of undesired eggs, small animals, and tiny plant pieces that may be hitching a ride.

Considerations When Doing Maintenance

Ensure the water garden is still isolated from natural waterways and flood-prone areas. Remove any uninvited plants and animals that may have colonized. To dispose of unwanted plants, freeze in a sealed plastic bag, microwave for 30 seconds, allow them to desiccate indoors, or burn plant material. After the plant is sufficiently deceased, dispose of it in the trash. Composting will not always be a successful method of disposal due to seed and reproductive plant part survivability. Rehome unwanted fish and other animals through a pet retailer, animal shelter, or fellow water gardener. Animals should never be released from captivity into natural waterways, and it is illegal to do so into Pennsylvania waters without authorization.

• Be mindful to properly manage the pH, nutrients, and organisms introduced into the system. 
• Remember, just because a plant or animal is invasive doesn’t mean it can’t be ordered online or purchased locally. 
• Unwelcome hitchhikers often accompany purchased plants. Plants and animals known to be invasive or prohibited in the state are often part of plant orders in the water or plant medium or used for packing.

If it seems likely that the plant has hitchhikers, you can clean emergent plants such as arrowhead (Sagittaria spp.) by dipping it in a 10% chlorine solution, swishing it around, and shaking it off. Rinse in tap water after 30 seconds. This technique should not be used on submerged plants like Elodea (Elodea canadensis).

Any hardy non-native plant or animal species may become the next problematic invasive species that can clog waterways and damage wildlife habitat. In addition, many closely related plants can hybridize with the native species, often passing on aggressive traits. Use native plants whenever possible.

Plant Selection

Each plant should have a purpose because space is limited. Those purposes might be color, height, algae deterrents, creating visual interest, and improving the health of the water garden. 

• Floating Plants: float on the water’s surface and survive with little to no soil. They help extract nutrients from the water, act as natural filters, and control algal growth. Examples include native Duckweeds (Lemna spp.).
• Submerged Plants: these are considered oxygenators of water gardens. Typically rooted, these plants are sold as cuttings and take time to establish. They provide food and shelter for young fish and reduce algal growth by absorbing nutrients. They can be planted as free-floating to self-establish or in pots sunk to the bottom. Examples include native Elodea species. 
• Shallow Marginal Plants: these plants can survive in 3 inches of standing water. They add color, height, and shape to water gardens and can help hide in-ground structures. They can be planted directly into soil or in underwater pots. Examples include native blue flag iris (Iris versicolor) and pickerelweed (Pontederia cordata).
• Deep Water Plants: these plants do well in 4 to 10 or more inches of water. Waterlilies are common deep-water plants, and many produce showy flowers and impressive leaves. Examples include native spatterdock (Nuphar advena) and fragrant water lily (Nymphaea odorata). 

Planting Methods

• Pockets are created during the construction of the water garden and hold aquatic plants in place. They are commonly found along the edges but can also be used in deeper areas to hold lilies. Plants eventually outgrow pockets and should be maintained to restrict plants to desired locations.
• Containers can be used like underwater pots for aquatic plants. Use regular topsoil without organic matter and containers with holes lined with burlap or landscaping fabric. Containers can be switched out easily as the plant outgrows them. 

Invasive Aquatic Plants

Any hardy non-native plant or animal species may become the next problematic invasive species that can clog our waterways and damage wildlife habitat. In addition, many closely related (same genus) plants can hybridize with the native species, often passing on aggressive traits. Our suggestion is to use native plants whenever possible.

When selecting plants, consider using species native to the region or non-invasive exotic plants. Never use any invasive plant unless it is well outside its hardiness zone, and even then, with caution.

The USDA plant hardiness zone map is the standard by which gardeners can determine which plants are most likely to thrive at a location. Pennsylvania ranges in hardiness zones from 5a in north central to 7b in southeastern and southwestern regions.

Choose a reputable nursery, ask if the vendor is aware of regional or federal restrictions and verify the scientific names are correct. Common names may be used for several different species, not all of which are harmless.

Invasive Aquatic Plants and Their Native Alternatives

Invasive: American Lotus

Nelumbo lutea

Notes: The American lotus is a floating-leaf aquatic plant with large white-yellowish flowers, making it a popular water garden plant. While beautiful, it can expand rapidly and completely cover a one-acre pond in three to four years. This plant spreads via rhizome roots and seeds and is listed in several neighboring states as invasive. The American lotus is native to the southern United States, Central America, and the Caribbean.

Native Replacement: Fragrant Water Lily

Nymphaea odorata

• Max Growth Height (ft): 5
• Flower Color: white, pink
• Bloom Time: March - October
• Water Body Type: bog, pond bottom, shallow water, water garden
• Water Quality Needs: somewhat acidic
• Light Requirements: sun, part shade, shade
• Soil Type: pond bottom with shallow water
• Hardiness Zones: 4 to 8
• More Information: floating aquatic plants with large, fragrant, showy flowers and flat, round leaves with long stems; reproduces via rhizome roots barely covered by soil; leaves provide shelter for fish and aquatic insects; muskrats may snack on stems.

Other Native Alternatives:

Pickerelweed (Pontederia cordata)

Invasive: Anchored Water Hyacinth

Pontederia azuria, formerly Eichhornia azurea

Notes: This rooted, perennial, aquatic plant was introduced to the United States through the water garden trade, and can be spread easily by fragmentation and hitchhiking. Anchored water hyacinth can form dense mats that block sunlight. This plant is on the Federal Noxious Weed list and should not be bought, sold, or propagated.

Native Replacement: Pickerelweed, Pickerel Rush

Pontederia cordata

• Max growth height (ft): 4
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: shallow water marshes, water gardens, bogs, ponds
• Light Requirements: sun, part shade
• Soil Type: sandy, sandy, loamy, clay, mud
• Hardiness Zones: 3 to 10
• More Information: marginal plant that survives as long as it does not dry out; flowers are showy and bloom throughout summer; can be divided regularly to keep from outgrowing desired space; attracts bees, butterflies, and birds

Other Native Alternatives: 

Spatterdock (Nuphar advena)

Invasive: Brazilian Waterweed, Brazilian Elodea, Anacharis

Egeria densa, Elodea densa

Notes: Brazilian waterweed, also sold as Anacharis, is a submerged aquatic perennial that can grow 10 ft or more as rooted or free-floating in depths up to 20 ft. Its showy flowers and oxygen-generating capabilities make it widely used in aquariums or water gardens.  All plants in the United States are male and can only reproduce vegetatively by fragmentation.

Native Replacement: Canadian Pondweed

Elodea canadensis

• Max growth height (ft): 2
• Flower Color: white
• Bloom Time: June - August
• Water Body Type: water gardens, small ponds
• Light Requirements: sun
• Hardiness Zones: 4 to 10
• More Information: This submerged aquatic plant can be grown anchored or free-floating in full sun water gardens; thrives in cool water; best controlled by planting in submerged containers and by clipping stems as needed; easy to control in smaller water gardens; not recommended for large ponds.

Other Alternatives

Water Celery, Eel Grass, Tape grass (Vallisneria Americana), Coontail (Ceratophyllum demersum)

Invasive: Curly-leaf Pondweed

Potamogeton crispus

Notes: Curly-leaf pondweed was introduced in the mid-1800s by aquarium hobbyists. It is now reported throughout the United States and is widespread in Pennsylvania. Reproduction occurs through rhizomes, turions, and fragmentation. Turions can remain viable in sediment for years until conditions are right and germination is triggered. This plant actively grows during winter months when most plants are dormant, giving it a competitive advantage. On occasion, it can spread by the movement of seeds, which can pass through the digestive systems of waterfowl and remain viable.

Native Replacement: Broad-leaved Pondweed; Floating Leaf Pondweed

Potamogeton natans

• Max growth height (ft): 1
• Flower Color: green
• Bloom Time: June - November
• Water Body Type: lakes, ponds, and ditches, highly organic substrate
• Water quality needs: mildly acidic, neutral, and basic
• Light Requirements: sun; does not tolerate shade
• Soil Type: sandy, loamy, and clay
• Hardiness Zones: 7 to 11
• More Information: submerged aquatic plant that can be used as an oxygenator; fast-growing, requires consistent monitoring to ensure it remains in desired area; creates habitat for fish spawning.

Other Native Alternatives:

Water Celery, Eel Grass, Tape grass (Vallisneria americana)

Invasive: Eurasian Watermilfoil

Myriophyllum spicatum

Invasive Eurasian watermilfoil (left), native coontail (right)

Notes: Eurasian watermilfoil is a submerged aquatic plant whose roots attach firmly to underwater sediment. In Pennsylvania, these plants usually die back to their roots in winter. This plant may be confused with bladderworts, hornworts, mermaid weeds, and other leafy milfoils. It reproduces by fragmentation which can live for weeks if kept moist. Although not a popular water garden plant, Eurasian watermilfoil is readily available for online purchase.

Native Replacement: Elodea, Canadian Pondweed

Elodea canadensis

• Max growth height (ft): 2
• Flower Color: white
• Bloom Time: June - August
• Water Body Type: water gardens, small ponds
• Light Requirements: sun
• Hardiness Zones: 4 to 10
• More Information: This submerged aquatic plant can be grown anchored or free-floating in full sun water gardens; thrives in cool water; best controlled by planting in submerged containers and by clipping stems as needed; easy to control in smaller water gardens; not recommended for large ponds.

Other Alternatives

Water Celery, Eel Grass, Tape grass (Vallisneria Americana), Coontail (Ceratophyllum demersum)

Invasive: European Frogbit

Hydrocharis morsus-ranae

Notes: European Frogbit is a free-floating aquatic plant that resembles a miniature water lily. Dense floating mats restrict sunlight and nutrient availability, displace native plant species, reduce biodiversity, and impact water flow. It reproduces through fragmentation or turions that spread or hitchhike. One plant can produce 100 to 150 turions per season, which float to the surface and begin to grow in spring. This popular water garden and aquarium plant can also be spread when released from enclosures.

Native Replacement: Watershield

Brasenia schreberi

• Max growth height (ft): 3
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: still waters, marshes, shallow water
• Water quality needs: lime-free
• Light Requirements: sun, part shade
• Soil Type: sandy, loamy, clay soils, mildly acidic and neutral 
• Hardiness Zones: 3 to 10
• More Information: perennial emergent aquatic plant with small lily pad-like leaves that float on the water’s surface; long single root attaches to the bottom; submerged plant parts are coated in jelly-like substance that prevents it from drying out; can become weedy; emits chemical that can deter growth of other nearby aquatic plants; food source for waterfowl; floating leaves provide shelter for fish and aquatic insects.

Other Native Alternatives:

Fragrant Water Lily (Nymphaea odorata)

Invasive: Fanwort

Cabomba caroliniana

Notes: Fanwort is a fast-growing freshwater perennial that can be found rooted or floating in waters of up to 20 feet. It is persistent, aggressive, and competitive, forming dense mats. Although fanwort is not typically used in water gardening, it is a popular aquarium plant worldwide. This plant can become invasive in natural waterways if intentionally released from an aquarium or accidentally flooded out of a water garden.

Native Replacement: Beck’s Water Marigold

Bidens beckii, Megalodonta beckii

• Max growth height (ft): 6
• Flower Color: yellow, green, brown
• Bloom Time: July - September
• Water Body Type: lakes, ponds, slow-moving rivers
• Light Requirements: sun
• Soil type: wet
• Hardiness Zones: 8 to 11
• More Information: This emergent, shallow-water plant produces showy yellow flowers above the water’s surface; submerged leaves are delicate and feathery; reproduces by fragmentation; good for use in shallow ponds and water gardens with mixed aquatic vegetation.

Other Native Alternatives:

Water Celery, Eel Grass, Tape grass (Vallisneria americana)

Invasive: Flowering Rush

Butomus umbellatus

Notes: Flowering rush is a perennial aquatic forb that can grow as an emergent plant along shorelines and a submerged plant in lakes and rivers. It is often unnoticed among other wetland plants until it blooms a distinctive spray of attractive flowers in late summer and early fall, making it a popular late bloomer along water garden margins. Once in a watershed, flowering rush spreads by rhizome roots, root pieces, and seeds. Movement by wildlife, water, anglers, and boaters and its use as a water garden plant have contributed to its spread.

Native Replacement: Spike Rush

Eliocharis palustris

• Max growth height (ft): 3
• Flower Color: green, brown
• Bloom Time: June - August
• Water Body Type: shore habitats
• Water quality needs: basic
• Light Requirements: part shade
• Soil Type: moist to wet, often alkaline, soils
• Hardiness Zones: 3 to 8
• More Information: This marginal, clumping perennial is grass-like and produces a small terminal flower; excellent for shore stabilization; used in water gardens, bog gardens, and along ponds and streams.

Invasive: Hydrilla, Water Thyme

Hydrilla verticillata

Notes: Hydrilla is an aggressively growing perennial plant that roots to the bottom of water bodies at depths of up to 12 ft. Its long, branching stems reach up to the water’s surface, where it quickly spreads and takes over. During the late growing season, small white tubers form on the roots and store food, enabling the plant to over-winter. Hydrilla reproduces through fragmentation. Although listed on the Federal Noxious Weeds list, Hydrilla is still bought and sold online as a “native elodea” for water gardens and ponds. Buyers should always double-check scientific names and purchase from reputable sellers.

Native Replacement: Coontail, Coon’s Tail, Hornwort

Ceratophyllum demersum

• Max growth height (ft): 12
• Flower Color: pink, yellow, blue
• Bloom Time: March - November
• Water Body Type: ponds, ditches
• Water quality needs: mildly acid, neutral, and basic
• Light Requirements: part shade
• Soil Type: sandy, loamy, clay
• Hardiness Zones: 7 to 10
• More Information: This fast-growing, submerged, rooting perennial tolerates shade better than many other submerged aquatic plants; great for pond oxygenation; typically remains submerged but can be seen floating at surface; provides shelter for young fish; reproduces asexually and should be monitored to prevent growth outside desired area.

Other Alternatives

Water Celery, Eel Grass, Tape grass (Vallisneria Americana), Elodea (Elodea canadensis)

Invasive: Mudmat

Glossostigma cleistanthum

Notes: Mudmat is a low-growing, mat-forming, invasive aquatic plant characterized by tiny petals and bright green leaves. It closely resembles some native mudwort species and can also be confused with emergent forms of some bladderworts. Forms dense monocultures made up of 10,000 to 25,000 individual plants per square meter creating thick carpets that can cover lake bottoms to depths greater than 6.5 ft. Initial introductions most likely occurred through aquarium releases and subsequent spread via hitchhiking on recreational equipment and animals.

Native Replacement: Common Bladderwort

Utricularia macrorhiza

• Max growth height (ft): 3
• Flower Color: red, yellow
• Bloom Time: June - September
• Water Body Type: bogs, ponds, slow-moving water
• Light Requirements: sun
• Hardiness Zones: 4 to 7
• More Information: a perennial aquatic bladderwort that grows suspended with no roots; leaves are finely divided with numerous bladders about 1/8"; bladder turns dark from devouring aquatic larvae including mosquito larvae; produces showy yellow flowers and does well alongside other aquatic plants; overwinters via turions in sediment; great for use in garden bog pool; can become weedy and even invasive in warm climates and should be monitored and controlled to maintain within desired area.

Invasive: Narrowleaf and Hybrid Cattails

Typha angustifolia, Typha x glauca

Notes: Cattails are aquatic perennials that grow in wetland areas and produce distinct velvety brown spikes of flowers. The two most widespread species in the United States are the native broadleaf cattail (Typha latifolia) and the invasive narrowleaf cattail (Typha angustifolia). The hybrid cattail (Typha x glauca) is produced when these two species cross, giving it characteristics of both species. The flower head of a cattail can produce 250,000 seeds, which can remain viable for up to 100 years. Seeds are dispersed by wind, and additional spread occurs through an extensive rhizome root system. Cattails are popular in ponds and large water garden margins. Buyers should double-check scientific names and ensure they are purchasing from a reputable buyer. The hybridized cattails (Typha x glauca) can sometimes only be identified from native species using DNA analysis.

Native Replacement: Broadleaf Cattail

Typha latifolia

• Max growth height (ft): 10
• Flower Color: yellow, green, brown
• Bloom Time: March - August
• Water Body Type: shallow pools or ponds
• Light Requirements: sun, part shade
• Soil Type: rich, wet soils. mud, saline tolerant
• Hardiness Zones: 3 to 10
• More Information: This native cattail is marginal and creates dense stands; provides habitat for birds and aquatic species; may grow aggressively, can be controlled by planting in containers; excellent accent plant for water gardens and ponds; can be used as privacy screen; reproduces through rhizome roots and seed dispersal.

Other Native Alternatives:

American Bur-reed (Sparganium Americanum), Northeastern Bullrush (Scirpus ancistrochaetus), Woolgrass (Scirpus cyperinus)

Invasive: Oxygen Weed, Curly Waterweed, African Elodea

Lagarosiphon major

Notes: Oxygen weed is an aquatic, submerged plant that can grow in dense mats. It is difficult to control, reproduces by fragmentation, and spreads via hitchhiking and release from water gardens. Although not yet documented in the United States, this plant has potential to be invasive in Pennsylvania if introduced. Oxygen weed can be bought and sold online as an “African elodea” and “curly waterweed.” Buyers should always double-check scientific names and purchase from reputable sellers. This plant should never be used outside of an aquarium setting.

Native Replacement: Elodea, Canadian Pondweed

Elodea canadensis

• Max growth height (ft): 2
• Flower Color: white
• Bloom Time: June - August
• Water Body Type: water gardens, small ponds
• Light Requirements: sun
• Hardiness Zones: 4 to 10
• More Information: This submerged aquatic plant can be grown anchored or free-floating in full sun water gardens; thrives in cool water; best controlled by planting in submerged containers and by clipping stems as needed; easy to control in smaller water gardens; not recommended for large ponds.

Other Alternatives

Water Celery, Eel Grass, Tape grass (Vallisneria Americana), Coontail (Ceratophyllum demersum)

Invasive: Parrot Feather

Myriophyllum aquaticum

Notes: Parrot feather forms dense mats and competes with native aquatic plants for space and resources, and creates habitat for mosquito larvae. It spreads through fragmentation and from whole plants, and it can be dispersed by people dumping aquariums into rivers and ponds. Animals can carry fruits and fragments to new waterbodies. Although parrot feather is not typically used in water gardening, it is a popular aquarium plant and can become invasive in natural waterways if intentionally released from an aquarium or accidentally flooded out of a water garden.

Native Replacement: Coontail, Coon’s Tail, Hornwort

Ceratophyllum demersum

• Max growth height (ft): 12
• Flower Color: pink, yellow, blue
• Bloom Time: March - November
• Water Body Type: ponds, ditches
• Water quality needs: mildly acid, neutral, and basic
• Light Requirements: part shade
• Soil Type: sandy, loamy, clay
• Hardiness Zones: 7 to 10
• More Information: this fast-growing, submerged, rooting perennial tolerates shade better than many other submerged aquatic plants; great for pond oxygenation; typically remains submerged but can be seen floating at surface; provides shelter for young fish; reproduces asexually and should be monitored to prevent growth outside desired area.

Other Alternatives

Water Celery, Eel Grass, Tape grass (Vallisneria Americana), Elodea (Elodea canadensis)

Invasive: Peruvian Primrose

Ludwigia peruviana

Notes: This invasive plant has showy, attractive yellow flowers making it a popular marginal plant in water gardens and ponds. Dense growth interferes with natural water flow and blocks sunlight. Reproduction occurs through heavy seeding or through suckers from submerged stems and stem fragments. Ninety-nine percent of the seeds produced by Peruvian primrose are viable and can remain in the seed bank for years.

Native Replacement: Water Willow

Justicia americana, Dianthera americana

• Max growth height (ft): 3
• Flower Color: white, pink, purple, violet
• Bloom Time: April - October
• Water Body Type: water gardens
• Light Requirements: sun, part shade
• Soil Type: sandy, sandy loam, medium loam, clay loam, clay
• Hardiness Zones: 4 to 10
• More Information: blooms throughout summer and reproduces through underground rhizome roots that provide habitat for aquatic insects and fish; larval food for Texan Crescentspot butterfly (Anthanassa texana); food source for muskrats and other semi-aquatic vertebrates; marginal plant that will grow in a few feet of water.

Invasive: Purple Loosestrife, non-native Loosestrifes

Lythrum salicaria, Lysimachia spp.

Notes: This hardy perennial was introduced via the water garden industry and escaped cultivation, invading natural waterways. One mature plant can produce over 1 million seeds in a year, which allows it to quickly spread. Purple loosestrife crowds out native species and creates monocultures along streams, ponds, and lakes. Although the invasive nature of purple loosestrife and other non-native loosestrifes is well known, many of these plants are still available for sale online and in stores.

Native Replacement: Pickerelweed, Pickerel Rush

Pontederia cordata

• Max growth height (ft): 4
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: shallow water marshes, water gardens, bogs, ponds
• Light Requirements: sun, part shade
• Soil Type: sandy, sandy loam, medium loam, clay, clay loam, mud
• Hardiness Zones: 3 to 10
• More Information: marginal plant that survives as long as it does not dry out; flowers are showy and bloom throughout summer; can be divided regularly to keep from outgrowing desired space; attracts bees, butterflies, and birds.

Other Alternatives

Swamp Milkweed (Asclepias incarnate), Swamp Loosestrife (Decodon verticillatus)

Invasive: Sacred Lotus, Asian Lotus, Indian Lotus

Nelumbo nucifera, Nelumbium speciosum, Nelumbo speciosa, Nelumbium nelumbo

Notes: Native to Asia, sacred lotus is a showy aquatic emergent perennial that produces large, dense colonies in natural areas. The showy flowers and floating leaves make this a popular water garden plant. Dense floating mats inhibit growth of native aquatic vegetation and decrease biodiversity. This plant is listed as invasive in several Great Lakes states. 

Native Replacement: Fragrant Water Lily

Nymphaea odorata

• Max Growth Height (ft): 5
• Flower Color: white, pink
• Bloom Time: March - October
• Water Body Type: bog, pond bottom, shallow water, water garden
• Water Quality Needs: somewhat acidic
• Light Requirements: sun, part shade, shade
• Soil Type: pond bottom with shallow water
• Hardiness Zones: 4 to 8
• More Information: floating aquatic plants with large, fragrant, showy flowers and flat, round leaves with long stems; reproduces via rhizome roots barely covered by soil; leaves provide shelter for fish and aquatic insects; muskrats may snack on stems. 

Other Native Alternatives:

Pickerelweed (Pontederia cordata)

Invasive: Water Chestnut, Water Caltrop

Trapa natans

Notes: Water chestnut is a rooted annual aquatic plant that grows in thick colonies. Its attractive leaf rosettes and edible nuts make this a popular choice for water gardens. Each plant can produce up to 15 nuts per season, each containing a single seed. It can also spread through fragmentation, where rosettes of floating leaves break apart and hitchhike or float to new locations. The sharp spines of the nut can also get caught on other objects, birds, and animals.

Native Replacement: Watershield

Brasenia schreberi

• Max growth height (ft): 3
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: still waters, marshes, shallow water
• Water quality needs: lime-free
• Light Requirements: sun, part shade
• Soil Type: sandy, loamy, clay soils, mildly acidic and neutral 
• Hardiness Zones: 3 to 10
• More Information: perennial emergent aquatic plant with small lily pad-like leaves that float on the water’s surface; long single root attaches to the bottom; submerged plant parts are coated in jelly-like substance that prevents it from drying out; can become weedy; emits chemical that can deter growth of other nearby aquatic plants; food source for waterfowl; floating leaves provide shelter for fish and aquatic insects.

Other Native Alternatives:

Broad-leaved Pondweed (Potamogeton natans)

Invasive: Water Hyacinth

Pontederia crissipes, formerly Eichhornia crassipes

Notes: Water hyacinth is a free-floating perennial that forms dense “rafts” of plant material in the water that can cover a water surface. Its beauty makes it a popular ornamental plant for ponds; however, its fast growth makes it one of the worst aquatic weeds in the world, as it can double its population in as little as six days. It reproduces by fragmentation and by forming plantlets at the end of a shoot that grow from the base of the stem.

Native Replacement: Pickerelweed, Pickerel Rush

Pontederia cordata

• Max growth height (ft): 4
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: shallow water marshes, water gardens, bogs, ponds
• Light Requirements: sun, part shade
• Soil Type: sandy, sand, loamy, clay, mud
• Hardiness Zones: 3 to 10
• More Information: marginal plant that survives as long as it does not dry out; flowers are showy and bloom throughout summer; can be divided regularly to keep from outgrowing desired space; attracts bees, butterflies, and birds.

Other Native Alternatives

American Pennywort (Hydrocotyle Americana), Spatterdock (Nuphar advena)

Invasive: Water Lettuce

Pistia stratiotes

Invasive water lettuce (left), native broad-leaved pondweed (right)

Notes: Water lettuce is a floating perennial that resembles an open head of lettuce. It forms colonies of rosettes that link together, blanketing the water’s surface, blocking waterways, and disrupting natural ecosystems. This plant can spread by fragmentation, stolons, and seeds.

Native Replacement: Broad-leaved Pondweed; Floating Leaf Pondweed

Potamogeton natans

• Max growth height (ft): 1
• Flower Color: green
• Bloom Time: June - November
• Water Body Type: lakes, ponds, and ditches, highly organic substrate
• Water quality needs: mildly acidic, neutral, and basic
• Light Requirements: sun; does not tolerate shade
• Soil Type: sandy, loamy, and clay
• Hardiness Zones: 7 to 11
• More Information: submerged aquatic plant that can be used as an oxygenator; fast-growing, requires consistent monitoring to ensure remains in desired area; creates habitat for fish spawning.

Other Native Alternatives:

Fragrant Water Lily (Nymphaea odorata)

Invasive: Water Spinach

Ipomoea aquatica

Notes: Water spinach is a freshwater, semiaquatic herbaceous plant that floats on the water's surface. Adventitious roots hang freely from stem nodes, which can break off and disperse, creating new infestations. It grows in ponds, marshes, swamps, very moist soils, ditches, and stream banks. Water spinach sometimes produces dense, impenetrable masses of vegetation that obstruct the flow of water and shade out competing plants. This plant is recognized as a Federal Noxious Weed.

Native Replacement: Watershield

Brasenia schreberi

• Max growth height (ft): 3
• Flower Color: blue, purple
• Bloom Time: March - November
• Water Body Type: still waters, marshes, shallow water
• Water quality needs: lime-free
• Light Requirements: sun, part shade
• Soil Type: sandy, loamy, clay soils, mildly acidic and neutral 
• Hardiness Zones: 3 to 10
• More Information: this perennial emergent aquatic plant has small lily pad-like leaves that float on the water’s surface and a long single root that attaches to the bottom sediment; submerged plant parts are coated in jelly-like substance that prevents the plant from drying during drought; can become weedy and emits chemical that can deter growth of other nearby aquatic plants and should be monitored and maintained; food source for waterfowl; floating leaves provide shelter for fish and aquatic insects.

Other Native Alternatives:

Fragrant Water Lily (Nymphaea odorata)

Invasive: Yellow Floating Heart

Nymphoides peltata

Notes: Yellow floating heart is an aggressive aquatic perennial which forms dense mats. It can be easily purchased in water garden specialty stores and online.  It reproduces by seed and fragmentation. This rooted aquatic plant creates star-shaped yellow flowers and thrives in slow-moving waters.

Native Replacement: Spatterdock, Yellow Pond Lily, Yellow Cow Lily

Nuphar advena

• Max growth height (ft): 1
• Flower Color: green-yellow
• Bloom Time: March - October
• Water Body Type: shallow lakes, ponds, bayous, bogs, streams
• Soil Type: sandy, loamy, and clay
• Light Requirements: part shade
• Hardiness Zones: 4 to 10
• More Information: has smaller, less showy flowers; can survive shaded, deeper waters; used in large ponds and water gardens;  slowly establishes colonies with flat, leathery, heart-shaped leaves that float;  produces underwater stems; reproduces via rhizome roots and seeds; best grown in containers for water gardens.

Other Native Alternatives:

Fragrant Water Lily (Nymphaea odorata)

Invasive: Yellow Flag, Yellow Flag, Pale Yellow Iris

Iris pseudacorus

Notes: This exotic iris is an emergent aquatic perennial with showy yellow flowers that grow 1- 3 ft tall, although some can reach up to 7 ft. Yellow iris reproduces vegetatively through rhizome roots, and it is a popular water garden plant for marginal areas by adding visual interest and showy blooms.

Native Replacement: Blue Flag Iris

Iris versicolor

• Max growth height (ft): 3
• Flower Color: green, brown
• Bloom Time: May - August
• Water Body Type: stream banks, marshes, swamps
• Water quality needs: acidic
• Light Requirements: sun, part shade
• Soil Type: mist, rich, acidic
• Hardiness Zones: 3 to 9
• More Information: this marginal perennial produces showy flowers that attract birds and beneficial insects; tolerates complete submergence but prefers riparian locations; spreads by self-seeding and through rhizome roots. 

Other Alternatives

Yellow Marsh Marigold (Caltha palustris), Cardinal Flower (Lobelia cardinalis)

Invasive Aquatic Animals

Aquatic animals can make popular additions to water gardens because their varied colors and movement build upon the existing visual elements. Aquatic animals should be chosen carefully due to their ability to move beyond the water garden and into natural waterways.

Snails and Fish

Non-native snails, like the popular Chinese and Japanese mystery snails, may seem like a harmless addition to a water garden, but there are several reasons to avoid them. Snails are generally easily moved or will move themselves under moist conditions. Birds can easily move snails on plant material, and some snails can survive digestion by fish. They are often intermediate hosts for parasites, and they have a large appetite for desirable vegetation, like the native plants found in a water garden. For these reasons, only native snails, which are adapted to their environment and the species in it, should be used in water gardens. 

Fish are often added to water gardens for visual interest; however, they can be a menace to a small water garden. The fish commonly used in water gardens are goldfish and koi, both of which are carp species from Asia, and are considered invasive in Pennsylvania. These fish consume aquatic plants at a high rate and uproot native plants while foraging, making the water cloudy. They also add nutrients to the system that must be removed using filters or balanced using plants.  Goldfish, Koi, and Carp will also grow quite large, oftentimes outgrowing their space. Despite this, they should never be released or allowed to escape into local waters.

Additional reasons to reconsider adding fish to your water garden refer to the saying, “If you build it, they will come.” Native amphibians such as frogs, toads, or salamanders may decide your water garden is a good place to reproduce or hang out. However, fish are predators that will eat their eggs. Other native animals that may move into a water feature include turtles, and birds and butterflies may come for a drink. One last consideration is the expense. Koi and goldfish are an expensive feature to add to a water garden, and they may attract birds, like the Great Blue heron, that consider expensive Koi a tasty snack. Rather than investing in exotic animals, rely on native species. Soon, you will have a thriving aquatic ecosystem in your backyard while maintaining the beauty and serenity of a water garden. 

Moving and Releasing Aquatic Animals

There are many ways that aquatic animals are moved between water bodies, such as recreational activities, swapping and sharing of species between water gardeners, and through accidental release. These activities should be avoided to prevent the introduction of non-native species to water bodies. This can be dangerous for the animal being moved as well as the new ecosystem. While a species may be native to one ecosystem, it may be invasive to another ecosystem just a few miles away.  Non-native species can disrupt native ecosystems and bring new pathogens and diseases with them. These microscopic dangers create new and unseen threats to the ecosystem. 

Aquatic animals should never be released from captivity. It is illegal to release any animals into waters of the Commonwealth without authorization, including turtles, fish, crayfish, and snails. Instead of releasing animals, pet owners should contact a local pet shop or adoption center or discuss euthanasia with a veterinarian. Trading plants and animals is a common practice, but this should only be done if water gardens are well maintained to prevent escape or flooding.

These tips are for water gardeners who have already added tropical or non-native species to their water gardens 

• Check on the animal regularly to be sure it’s safe and still within its enclosure. 
• Check and maintain the water garden or enclosure regularly to ensure there are no potential points of release or escape.
• Ensure the animal will not wash into a natural waterway during flooding or heavy rain.

Invasive Aquatic Animals and Their Native Alternatives

Invasive: Chinese and Japanese Mystery Snails

Often sold as Japanese Trapdoor Snails (Cipangopaludina chinensis, Cipangopaludina japonica)

Invasive mystery snails (left), native pointed Campeloma (right)

Notes: Mystery snails (Cipangopaludina spp) are large freshwater snails commonly sold for use in freshwater aquariums and garden ponds. Their popularity in the aquarium industry has contributed highly to their spread across the United States.

Native Replacement: Brown Mystery Snail or Pointed Campeloma

Campeloma decisum

• Max growth: length 4 cm
• Primary Colors : light yellowish olive, tan, brown, rust
• Reproduction Rate: mate once a year; 
• Water Body Type: flowing water, lentic environments, lakes
• Water quality needs: limited by salinity
• Food Sources: detritivore, feeds on particulates in soft sediment and facultatively through filtration
• Overwinter in PA? (Y/N): Y
• More Information: small freshwater snail generally found in rivers and lakes with sandy substrate; the shell spire is elongated, and the body is rounded; has an operculum that allows the shell to seal off; food source for fish, diving waterfowl, turtles, and crayfish. 

Invasive: Goldfish

Carassius auratus

Invasive goldfish (left), native golden shiner (right)

Notes: The Goldfish is a member of the carp and minnow family. It was one of the first aquatic invasive species to reach North America, arriving in the 1600’s as an ornamental fish for aquariums and water gardens. It is now one of the world’s most widespread invasive species. Goldfish have been intentionally introduced for ornamental purposes to ponds, fountains, and small lakes from which they may escape through connecting waters. Many introductions of goldfish were also due to their use as live bait. In addition, goldfish are often released into the wild by pet owners not realizing the environmental repercussions of setting the fish free.

Native Replacement: Golden Shiner

Notemigonus crysoleucas

• Max growth length: 30 cm
• Primary Colors: silver to gold sides, dark stripe along midline
• Reproduction Rate: 4-5 spawning times per year, 200,000 is max fecundity
• Water Body Type: lakes, rivers, bays; slow moving or stagnant water
• Water quality needs: Temp range = 0-35 C, Salinity = 0-14), Reproductive temp= 20-27
• Food Sources: zooplankton and phytoplankton
• Overwinter in PA? (Y/N): Y
• More Information: A small to mid-sized freshwater fish from the carp and minnow family. Adult fish vary in color from silver to brassy gold, with clear to yellowish fins. Juveniles are slender with a brownish back, dusky stripe on the sides, extending from the eye to the snout, and silvery belly. They are common bait fish in the Eastern United States but are considered invasive in several western states. They prefer relatively warm, still waters with dense vegetation, and they can tolerate low oxygen levels. Golden shiners feed on aquatic and flying insects and algae and can become prey for larger fish.

Invasive: Koi Fish, Common Carp, and other carp species

Cyprinus rubrofuscus "koi", Cyprinus carpio, Cyprinus species

Invasive kio fish (left), native pumpkinseed (right)

Notes: Varieties of common carp include Koi, which are popular in small ponds and water gardens. Introduction of common carp causes dramatic ecological disruptions at both the community and ecosystem levels. The common carp is omnivorous, feeding on benthic aquatic organisms such as insect larvae, worms, mollusks, and zooplankton as well as the stalks, seeds, and leaves of aquatic plants. This foraging behavior increases the turbidity of the water, which releases phosphorus,  increases algae growth, and prevents the growth of native aquatic plants.

Native Replacement: Pumpkinseed 

Lepomis gibbosus

• Max growth length: 40 cm
• Primary Colors: back is olive, iridescent blue lines and golden flecks
• Reproduction Rate: Females carry 600-3000 eggs
• Water Body Type: lakes, ponds, and streams
• Water quality needs: temp range= 4-32C, 10 practical salinity units, reproductive temp= 13-28C C
• Food Sources: zooplankton and phytoplankton, worms, insects, crustaceans
• Overwinter in PA? (Y/N): Y
• More Information: This medium-sized freshwater sunfish has an olive, oval body with iridescent blue lines and golden flecks; the earflap is black with a bright red or orange spot near the center; the Pumpkinseed feeds on mussels, clams, snails, insects, and crustaceans.

Other Native Alternatives

Largemouth Bass (Micropterus salmoides), Bluegill (Lepomis macrochirus)

Other Aquatic Animals to Avoid

Red-Eared Slider 

Trachemys scripta elegans

Notes: The Red-eared slider is a hardy freshwater turtle that is popular as an aquarium pet in the United States. It gets its name from the broad red stripes present behind each eye. Its popularity in the pet trade has helped account for its numerous introductions worldwide. It is now designated as one of the “100 World’s Worst Invaders”. Adult sliders can reach lengths of up to 12 in, and unsuspecting owners are rarely prepared to continue maintaining them in captivity at this size. The owners then dispose of them by releasing them into local waterways and impoundments, which has led to their introduction and spread into the natural environment.

Yellow-Bellied Slider

Trachemys scripta scripta

Notes: The Yellow-bellied slider is a large, semi-aquatic, basking turtle that can be found resting on logs, stumps, or rocks when the weather is mild and the sun is out. It can live for more than 25 years, with no signs of old age. This species can mate with the red-eared slider (Trachemys scripta elegans), producing hybrids that are often sold as pets. Because the Yellow-bellied slider is popular in the pet industry, intentional pet releases, as well as escapes into the natural environment are the most likely vectors for its spread. Because of their longevity and large size, unprepared pet owners may release them into local waterways and impoundments, which has led to their introduction and spread into the natural environment.

Pond Loach

Misgurnus anguillicaudatus

Notes: This small eel-like fish gets its name from its ability to forecast the weather. It is sensitive to changes in barometric pressure; therefore, increases in activity and swimming in fast circles can indicate that major weather changes are imminent. This species is also popular in the aquarium trade because it is hardy and has a voracious appetite that can help keep tanks clean. Unfortunately, the release of this species into water bodies has caused negative impacts to water quality, native species, and the food web.

Contributors

This publication has been updated jointly by Penn State Extension and Pennsylvania Sea Grant through support from the Richard King Mellon Foundation and the Great Lakes Commission.

Reviewers

Prepared by Diane Oleson, natural resources extension educator in York County

Edited and updated in 2024 by Amber Stilwell, Coastal Outreach Specialist with Pennsylvania Sea Grant and Extension Educator with Penn State Extension. 

The authors wish to thank the following individuals who served as reviewers for versions of this publication:

• Andy Yencha, Water Resources Educator, Cumberland County,  Penn State Extension
• Brian Pilarcik, Watershed Specialist, Crawford County Conservation District
• Bryan Swistock, Water Resources Extension Associate
• Dana Rizzo, Water Quality Extension Educator, Westmoreland County, Penn State Extension
• Greg Hitzroth, Aquatic Invasive Species Outreach Specialist, Illinois-Indiana Sea Grant
• Sara Stahlman, Extension Leader, Pennsylvania Sea Grant
• Sarah Whitney, Director, Pennsylvania Sea Grant
• Sean Hartzell, Aquatic Invasive Species Coordinator, Pennsylvania Fish and Boat Commission
• Susan M. Boser, Water Quality Extension Educator, Beaver County, Penn State Extension
• Thomas McCarty, Water Quality Extension Educator, Cumberland County, Pen State Extension

Resources

Web Resources

• Plant Hardiness Zone Map. United States Department of Agriculture (USDA)
• USDA PLANTS database. Check a garden addition for being native or introduced in your state.
• Nonindigenous Aquatic Species Database. United States Geological Survey (USGS)
• Invasive Plants. United States National Arboretum
• Habitattitude™
• Center for Agriculture and Bioscience International (CABI).
• Invasive Plant Atlas of the United States (2018).
• Pennsylvania Sea Grant (2012). Pennsylvania’s field guide to aquatic invasive species. 
• The University of Texas at Austin (2023). Lady Bird Johnson Wildflower Center. 
• Carnivorous Plant Nursery (2023). Utricularia macrorhiza.
• Environmental Conservation Online System (ECOS)(n.d). Northeastern bulrush (Scirpus ancistrochaetus). U.S. Fish & Wildlife Service. 
• Gardenia.net (2023). Northeastern bulrush (Scirpus ancistrochaetus).
• Haynes, Cindy (2018). Water Gardens: Aquatic Plants. Iowa State University Extension and Outreach. 
• H, Rebecca (2020). How to Plant & Grow American Water Willow (Justicia americana). Pond Informer. 
• Invasive.org (2010). Parrot-feather. 
• Minnesota Department of Natural Resources (2023). Wild Celery (Vallisneria americana).
• Minnesota Wildflowers.info (2006-2023). Bidens beckii (Water Marigold).
• Native Plant Trust (2023). Bidens beckii — Beck's beggar-ticks, Beck's water-marigold.
• New Moon Nursery (2023). Lobelia cardinalis: Cardinal flower. 
• Penn State Extension (2023). Purple Loosestrife in Pennsylvania.
• Pennsylvania iMap Invasives (n.d.). Yellow Iris (Iris pseudacorus).  
• Pennsylvania Sea Grant (2023). Curly-leaf pondweed.  
• Pennsylvania Sea Grant (2023). Eurasian watermilfoil.  
• Pennsylvania Sea Grant (2023). Fanwort.
• Pennsylvania Sea Grant (2023). Hydrilla.  
• Pennsylvania Sea Grant (2023). Mudmat.
• Pennsylvania Sea Grant (2023). Water chestnut.  
• Pennsylvania Sea Grant (2023). Water hyacinth.
• Pennsylvania Sea Grant (2023). Water lettuce.  
• Pennsylvania Sea Grant (2023). Yellow floating heart.  
• Puisis, Erica (2023). How to Grow and Care for Bidens. The Spruce.  
• Rhode Island Department of Environmental Management (2018). Fact Sheet: American Lotus.
• Sharp, Shannon (n.d.). Plant of the Week: Watershield (Brasenia schreberi). U.S. Forest Service; U.S. Department of Agriculture.
• University of Florida (2023). Eichhornia azurea: Rooted water hyacinth. Center for Aquatic and Invasive Plants.  
• University of Florida (2023). Lagarosiphon major: African elodea. Center for Aquatic and Invasive Plants.  
• United State Department of Agriculture (2020). Weed Risk Assessment for Ipomoea aquatica Forssk. (Convolvulaceae) – Water spinach.  
• Wetland Plants Inc (n.d.) Vallisneria americana (American Eelgrass).
• Wishah, L.O., and K.M. Schroeder (2023). Ludwigia peruviana (L.) H. Hara: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL 
• Wisconsin Department of Natural Resources (n.d.). Sacred lotus (Nelumbo nucifera).
• Cordeiro, J. (2008), Ormes, M. (2015). Campeloma decisum: Pointed Campeloma. NatureServe Conservation.
• Dillon, R. T., Jr. et al (2019).  The Freshwater Gastropods of North America Volume 1: Atlantic drainages, Georgia through Pennsylvania. FWGNA press.
• Mulcrone, Renee (2014). Campeloma decisum (Online), Animal Diversity Web.  
• Nemesis Marine Invasions Lab (n.d.). Lepomis gibbosus.  
• Nemesis Marine Invasions Lab (n.d.). Lepomis macrochirus. 
• Nemesis Marine Invasions Lab (n.d.). Micropterus salmoides.
• Nemesis Marine Invasions Lab (n.d.). Notemigonus crysoleucas. 
• Nico, L., & Neilson, M.E. (2023). Notemigonus crysoleucas (Mitchill, 1814). U.S. Geological Survey, Nonindigenous Aquatic Species Database.
• Pennsylvania Sea Grant (2023). Common Carp.
• Pennsylvania Sea Grant (2023). Goldfish.  
• Pennsylvania Sea Grant (2023). Invasive reptiles: red-eared slider (Trachemys scripta elegans).
• Pennsylvania Sea Grant (2023). Yellow-bellied slider.
• Sims, J. (2006). "Notemigonus crysoleucas" (Online), Animal Diversity Web.  
• Texas Parks & Wildlife (n.d.). Golden Shiner (Notemigonus crysoleucas) 

Other Resources

• Rhoads AF & Block TA. 2011. Aquatic Plants of Pennsylvania, University of Pennsylvania Press, Philadelphia PA, 308 pp.
• Rhoads AF & Block TA. 2007. The Plants of Pennsylvania, 2nd Edition, University of Pennsylvania Press, Philadelphia PA, 1042 pp.

Photo Credits

Photo Credits

• Brasenia schreberi - Brian Pilarcik, Crawford County Conservation District
• Bidens beckii, Megalodonta beckii - Tab Tannery, Bidens beckii (marsh marigold) (2015), Flickr, Licensing: CC BY-NC-SA 2.0 Deed | Attribution-NonCommercial-ShareAlike 2.0 Generic | Creative Commons
• Butomus umbellatus - Flowering spikerush, RAHoward- R.A. Howard. ©Smithsonian Institution. Courtesy of Smithsonian Institution, Richard A. Howard Photograph Collection
• Cabomba caroliniana - Brian Pilarcik, Crawford County Conservation District
• Campeloma decisum - Sean Hartzell, Pennsylvania Fish and Boat Commission
• Carassius auratus - Jim Grazio, Ph.D., Pennsylvania Department of Environmental Protection
• Ceratophyllum demersum - Coontail, Vic Ramey, IFLAS, University of Florida
• Cyprinus carpio - Koi, Stan Shebs, Wikipedia Commons
• Decodon verticillatus - Amber Stilwell, Pennsylvania Sea Grant, Penn State Extension
• Eliocharis palustris - Spikerush, Jennifer Anderson @ USDA-NRCS PLANTS Database
• Egeria densa - Brazilian egeria, Graves Lovell, Alabama Department of Conservation and Natural Resources, Bugwood.org
• Eichhornia azurea - Anchored water hyacinth, Kurt Stueber, Max-Planck-Institute for Plant Breeding Research, Cologne, Bugwood.org
• Eichhornia crassipes - Water hyacinth, Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
• Elodea canadensis - Elodea, Dana Rizzo, Penn State University
• Hydrocharis morsus-ranae - Common frogbit, Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
• Hydrilla verticillata - Hydrilla, Chris Evans, River to River CWMA, Bugwood.org
• Ipomea aquatica - Swamp morning glory, Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org swamp
• Iris versicolor - Blueflag iris, Jennifer Anderson @ USDA-NRCS PLANTS Database
• Iris pseudacorus - Yellowflag iris, Nancy Loewenstein, Auburn University, Bugwood.org
• Justicia americana - Water-willow, Larry Allain @ USDA-NRCS PLANTS Database
• Lagarosiphon major - Oxygen weed, Rohan Wells, National Institute of Water and Atmospheric Research, Bugwood.org
• Lepomis gibbosus - Josh Grassi, Pennsylvania Department of Environmental Protection
• Lepomis macrochirus - Mark Lethaby, Pennsylvania Sea Grant
• Lobelia cardinalis - Steve Laskowski, Pennsylvania DCNR Bureau of Forestry
• Ludwigia peruviana - Primrose-willow, Amy Ferriter, State of Idaho, Bugwood.org
• Lythrum salicaria - Purple loosestrife, John D. Byrd, Mississippi State University, Bugwood.org
• Misgurnus anguillicaudatus -Gourami Watcher, Dojo loach (Misgurnus anguillicaudatus) in aquarium(2011), Retouched picture,digitally altered by author; modifications: darkened and cropped, WikiMedia Commons, Licensing: CC BY 3.0 Deed | Attribution 3.0 Unported | Creative Commons
• Myriophyllum aquaticum - Parrotfeather, John M. Randall, The Nature Conservancy, Bugwood.org
• Myriophyllum spicatum - Eurasian watermilfoil, Barry Rice, sarracenia.com, Bugwood.org
• Notemigonius crysoleucas - Sean Hartzell, Pennsylvania Fish and Boat Commission
• Nuphar lutea - Spatterdock, Bryan Swistock, Penn State University
• Nymphoides peltata - Yellow floatingheart, David Cappaert, Michigan State University, Bugwood.org
• Nymphaea odorata - Fragrant water lily, Joseph Dougherty, ecophotog@yahoo.com
• Pistia stratiotes - Waterlettuce, Troy Evans, Great Smoky Mountains National Park, Bugwood.org
• Pontederia cordata - Pickerelweed, Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database
• Potamogeton crispus - Bryan Swistock, Penn State Extension
• Salvinia molesta - Giant salvinia, Larry Allain @ USDA-NRCS PLANTS Database
• Trachemys scripta elegans - Pennsylvania Sea Grant
• Trachemys scripta scripta - John White, Virginia Herpetological Society
• Trapa natans - Water-chestnut, Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
• Typha angustifolia, Typha x glauca - Blue Planet Green Living