Invasive Plants and Weeds
Invasive plants and weeds and the best ways to manage them
Nothing leads to more conflicts among gardeners than having neighbors allow their plots to become “weed seed banks”. Not only are they unsightly but the seeds will find their way into adjacent plots via surface water, wind, or gravity. They are a shared problem in close-quarter gardens like a community garden. The term “invasive”; is used for the most aggressive species. These species grow and reproduce rapidly, causing major disturbance to the areas in which they are present. The Badger Prairie Garden shed has various tools – parsnip predator, etc. for use in the garden. Please remember to clean and return community tools.
The list below is based on issues we’ve seen the last couple years and expect to be present this year. We will likely find other weeds and problems that pop up from time to time, so this list and plan will be updated as we go.
Wild Parsnip– dig with a parsnip predator or a transplant (long narrow blade) shovel at or before flowering stage to avoid seed set. Beware of phytophototoxicity, wear gloves, long pants and long shirt sleeves when removing wild parsnip, and avoid contact with skin. Any plant sap or juices that contact the skin will cause a rash, blistering and discoloration of skin when exposed to sunlight. When digging is not an option, mow plants to the ground to prevent seed set.
Canada Thistle – dig as much of the root as possible, roots are deep and spread horizontally at a depth of about 8-10” below the soil making it difficult to dig them completely. Especially in areas where there are good plants nearby, this method may cause too much soil disturbance. Pulling or cutting/mowing them to weaken the plant and prevent seed set is the best way to control them when digging is not possible.
Bull thistle– dig or pull when possible to remove, or mow to prevent seed set.
Burdock– Dig using parsnip predator or shovel, try to remove as much root as possible. If you’re adventurous, you could peel, cook and eat the roots you harvest! Biennial life cycle, first year the plant produces a rosette of large leaves near the ground, the second year it produces a tall flower stalk that results in burs that will stick to clothing.
Curly Dock – Curly dock, a perennial broadleaf plant, usually grows in wet areas and is frequently associated with overwatering or standing water in low areas. Dig as much root as possible, has a tough taproot.
Giant Ragweed – if plants are isolated, or colonies are small, they can be pulled or dug. If colonies are large, they can be cut or mowed just before or during flowering. These weeds are a major irritant to people with allergies, cutting or mowing them before they release their pollen in late summer or early fall will prevent allergic reactions.
Queen Anne’s Lace
Queen Anne’s Lace – dig plants with a parsnip predator or a transplant shovel before or during flowering to prevent seed set. When populations are large mow them to weaken the plant and prevent seed set. Biennial life cycle, has carrot like foliar growth the first season, and will produce tall flower stalks and flowers that set seed the second year.
Motherwort – Can be dug or pulled, if populations are high, mowing to prevent seeding will prevent it from becoming a bigger problem in the future.
Purslane – carefully dig or pull, any leaf or stems left behind can root and grow
Garlic Mustard – Dig or pull plants before they reach advanced stages of flowering. If they have reached the flowering stage, plants must be bagged and disposed of in the trash. Large patches may be mowed with a string trimmer at early stages of flowering by obliterating the entire plant from the top of the plant to the ground.
Dame’s Rocket – Don’t be fooled by this pretty flower, it is a relative of Garlic Mustard and can become a problem plant very quickly because of the large quantity of seeds it produces! Dig or pull plants before they reach advanced stages of flowering. If they have reached the flowering stage, plants must be bagged and disposed of in the trash. Large patches may be mowed with a string trimmer at early stages of flowering by obliterating the entire plant from the top of the plant to the ground.
Annual Weeds to pull before or during flowering to prevent them from reseeding:
These can be controlled by cutting resprouts that grow back from previously cut stumps using a brush cutter of hand pruners or loppers.