Weed Management

Weeds are a persistent problem for any home gardener. They compete with garden plants for nutrients, moisture, and sunlight. In this section, you’ll find information on weed management and control of purple loosestrife, ragweed, pokeweed, knotweed, pineappleweed, and poison ivy. Find tips on mulches and integrated pest management.

Garden Weeds: Identification and Management

The official definition of a weed is a plant whose undesirable qualities outweigh its good points. For the home gardener, it’s essential to control weeds because they can be very unsightly as well as compete with the desirable plants for nutrients, light, and moisture.

One increasingly common weed in lawns and landscape beds is Japanese stiltgrass. It is considered an invasive species, along with many others, such as poison ivy.

If you’ve got weeds in your garden, it’s important to know how to manage and control them. Herbicides are an option, but other more environmentally friendly methods can also be used.

Mulching is a mechanical method of weed control that is very effective for home fruit plantings. In the home fruit garden, you can use mulches to eliminate weeds or slow their growth. Mulching has the added advantage of improving soil structure and fertility, but it does have to be done properly if you want it to be effective.

Invasive Garden Plants

Weeds are a problem, but you’ve got a real problem on your hands when the weed is an invasive species. Invasive plants spread quickly because they are not limited by pests, diseases, or predators. They grow and reproduce rapidly, can thrive in a variety of situations, even adverse conditions, and require specific control methods. Before you know it, your garden could be completely taken over. Even desirable plants can take over areas you did not intend.

Here are some invasive plants to be aware of:

• Butterfly bush: Originally from Asia, it has no natural predators in the US.
• Bull thistle: This biennial can be controlled through regular mowing, but this doesn’t prevent its seeds from blowing into other areas.
• Poison ivy: This native woody, perennial vine contains resinous compounds called urushiols, causing inflammation, itching, and blistering when in contact with the skin.
• Tree of heaven: A popular tree with the non-native, invasive spotted lanternfly.
• Japanese honeysuckle: The growth of this invasive, non-native climbing vine is very aggressive and will quickly climb over other desirable plant material.
• Wild carrot: Also known as Queen Anne’s lace, this biennial is not considered a weed by everyone. Hand removal is one option, as is the application of a post-emergent herbicide.
• Jimsonweed: This invasive species can reach a height of over five feet, and all parts of the plant are poisonous to animals and humans.
• Multiflora rose: In Pennsylvania, Rosa multiflora is considered an invasive shrub and noxious weed.
• Common pokeweed: In its first year, you can remove it by hand, but once it’s become established, it can be difficult to eradicate due to the size of its taproot.
• Invasive orchids: To effectively control Epipactis helleborine, you have to remove all the roots, otherwise new plants will develop from the remaining root tissue.
• Poison hemlock: Commonly found along roadsides, fields, and wet areas, this invasive species is poisonous to humans and animals.
• Mulberry weed: This plant resembles the seedling of a mulberry tree but has hairy stems and leaves.
• Ragweeds: These are a member of the Aster family and have a history of herbicide resistance.
• Carpetweed: This low-growing multi-shoot annual grows into a circular mat.
• Pineappleweed: This summer or winter annual has flower heads that are rounded and greenish-purple. It also has a distinct odor that resembles a pineapple.

Garden Weeds: Herbicides Application

You can use herbicides in the home garden, but their usefulness depends on several factors. Understanding the herbicides will help you use them more effectively and safely.

You must use the proper herbicide formulations if you want to prevent damage to non-target plants. Do you know what the active ingredients are in the herbicide you are using? Are they amines or esters, for example? Knowing the difference will dramatically increase your weed control.

You must also be aware of herbicide drift and drift-related damage, especially if you want to avoid the risk of a potential lawsuit. Glyphosate is a systemic herbicide that can take years to break down when over-sprayed onto the bark of young trees.

If your spray applications have to be reported to the EPA, you will need to keep a record of spray products you used.