Native Shrubs for Pollinators
Planting a pollinator-friendly garden has become easier these days. Look at any of the top gardening websites, including Extension, to find plant lists. The actual pollinator plants are readily available at local and regional garden centers and online vendors. Many obstacles that once existed have been removed.
Native plants are always highly recommended to plan a beneficial pollinator habitat; most are perennials. Native and non-native/non-invasive annuals are suggested as nectar and pollen sources as they have long-lasting blooms throughout summer. Nowadays, many of us have read the research by Dr. Doug Tallamy and his colleagues touting the host benefits of certain tree species, i.e., oaks, cherries, and willows. Often, these trees may already be present in the landscape around your home, or you have found ways to incorporate them. To have a successful pollinator habitat, a variety of plant types, structures, and sizes is needed, along with varying bloom times.
Shrubs are often overlooked in the planning stages or on recommended plant lists for pollinator-friendly gardens. However, their value is increasingly recognized, as they offer much to pollinators. The Pennsylvania Pollinator-Friendly Garden certification includes a great list of both trees and shrubs to include in your design. The Pollinator Victory Garden by Kim Eierman provides reasons to plant more shrubs for pollinators. A single shrub of good size can provide more flowers, i.e., nectar and/or pollen, than a single perennial plant. Some flowering shrub species bloom earlier than perennials and annuals, providing a necessary food source for the native bees. Many native shrubs are larval hosts for butterflies and moths. Add shrubs along the edges of the landscape or directly in the garden area. There are pollinator-friendly shrubs for most light and soil conditions found in the home garden.
Below is a short list of native shrubs that work well in most Pennsylvania gardens. These species provide a bevy of habitat functions for bees (native and honey), butterflies and moths, wasps, flies, and beetles, as well as other wildlife.
Buttonbush (Cephalanthus occidentalis)
Buttonbush is a favorite of pollinators. One of its common names is "honey ball," which speaks volumes to its role as a pollinator-friendly plant. The pincushion-like flowers, a valuable nectar and pollen source for myriad species, bloom throughout the summer. Native bees, honey bees, butterflies, moths, and more have been documented on the multi-stemmed 6- to 12-foot shrubs. It is an important food source for adult titan sphinx and hydrangea sphinx moths. Buttonbush prefers light shade to shade and wet feet. If you have moist areas or even areas that pool water in your garden, plant your buttonbush there, and it will thrive. In addition to its benefit to pollinators, buttonbush produces red fruit, which contains clusters of nutlets and is a significant food source for over 50 species of waterfowl and songbirds.
Pussy Willow (Salix discolor)
Pussy willow is a late winter/early spring bloomer and provides both nectar and pollen to pollinators. Note that the genus Salix is among the top three genera listed by Dr. Doug Tallamy to host butterfly and moth caterpillars. Salix discolor is the earliest bloomer of the native willows. The silver-gray, fuzzy catkins are a delight for gardeners and pollinators alike as they send the message that spring is truly on its way.
The catkins become an essential food source for early-emerging pollinators such as queen bumblebees. Pussy willow is the host plant for viceroy and mourning cloak butterflies. The multi-stemmed shrub, which can reach heights of 20 feet, supports many other butterflies, bees, gnats, syrphid flies, birds, small mammals, and more. Site pussy willow in a sunny but moist area. The shrub has vigorous growth and needs a good pruning every few years to maintain a good habit and encourage new growth.
Spicebush (Lindera benzoin)
A member of the laurel family (Lauraceae). The common name and species name, derived from an Arabic word meaning "aromatic gum," refer to the plant's fragrant nature. Spicebush is dioecious, meaning that male and female flowers are on separate plants, so for the plant to produce fruit, female plants need a male pollinator. A deciduous shrub, it is found growing naturally in open forests, swamp margins, and along forest edges, rivers, streams, and lakes, and is well suited for use in shrub borders, woodlands, and pollinator and rain gardens.
Spicebush provides an early nectar source for small pollinators, including bees, flies, and even ants. It is the larval host plant for Palamedes swallowtail (Papilio palamedes), spicebush swallowtail (Papilio troilus), and Promethea silkmoth (Callosamia promethea). Spicebush prefers moist, well-drained soils and partial shade, but it can be grown in full sun if watered adequately. Forming a broad, rounded habit, it typically grows 6 to 12 feet tall, with light green, oblong-obovate leaves that turn bright yellow in the fall.
Summersweet (Clethra alnifolia)
Summersweet and sweet pepperbush are common names that indicate that Clethra alnifolia has a sweetness that attracts pollinators. White or pink flower spikes, 3 to 6 inches long, produce high-quality nectar and pollen from mid-summer to late summer. The shrub supports a variety of pollinators, including bees, butterflies, and hummingbirds. Summersweet has a clumping habit reaching 6 feet tall, though it can grow to 12 feet if conditions are optimal. Site summer sweet in moist, acidic soil in full sun to partial shade. Flowers bud on new growth. Therefore, a good pruning every year or every two years keeps the shrub invigorated. Summersweet is relatively pest- and disease-free, except when drier conditions weaken the plant.
Winterberry (Ilex verticillata)
Winterberry is a deciduous holly that has inconspicuous green flowers in late spring/early summer. Despite the indistinct flowers, they are a nectar source for butterflies, honey bees, and other small pollinators. Winterberry plays host to Henry's elfin butterfly. Naturally found along the edge of woods, the 6- to 10-foot tall clumping shrub can do well in shade to full sun.
To experience the full effect of winterberry, i.e., the berries, a female plant and a male plant are needed. Winterberries are dioecious plants, where a plant with male parts is needed to pollinate a plant with female parts for fruit production. The University of Connecticut Plant Database lists cultivars and varieties currently available to home gardeners. If you garden for pollinators, expect other wildlife to benefit, too. The berries of winterberry are of high nutritional value to many species of songbirds, including cedar waxwings, grosbeaks, and orioles.
Witch Hazel (Hamamelis virginiana)
A member of the witch hazel family (Hamamelidaceae). Its genus name comes from the Greek words hama, meaning "at the same time," and melon, meaning "apple" or "fruit," referring to the plant’s ability to have both flowers and fruit at the same time. A woody plant, witch hazel grows naturally in woodland forests and along stream banks and is well suited for use in shrub borders, woodland or pollinator gardens, or for creating a tall hedge or screen. Growing as a small, deciduous, multi-stemmed tree or shrub, large, crooked, spreading branches form an irregular, open crown growing 15 to 30 feet in height. Witch hazel prefers moist, acidic soil, and while it can be grown in full sun to part shade, the best flowering occurs in full sun. Up to 6 inches long, their leaves are broadly oval with large, wavy teeth and turn shades of yellow in the fall.
Witch hazel can bloom any time from late fall to late winter. Fragrant, yellow flowers bloom in clusters along the branches. Four slender, crinkly, ribbon-like petals form the ½ to ¾ inch long flowers. While several species of bees, flies, gnats, and small wasps have all been documented visiting their flowers to feed on their sticky nectar and pollen, it is postulated that the primary pollinators may be nocturnal moths in the Noctuidae family. These moths can remain active at cooler temperatures while other pollinators cannot, by vibrating their wing muscles to raise their body temperature. Witch hazel is the larval host plant of a number of moth species, including Drexel's datana (Datana drexelii), witch hazel dagger (Acronicta hamamelis), and mustard sallow (Pyreferra hesperidago).
