INVASIVE PLANTS
These pages are best viewed with a desktop browser.
Purple Loosestrife invades marshes and lakeshores, replacing cattails and other wetland plants. The plant can form dense, impenetrable stands which are unsuitable as cover, food, or nesting sites for a wide range of native wetland animals including ducks, geese, rails, bitterns, muskrats, frogs, toads, and turtles. Many rare and endangered wetland plants and animals are also at risk.
Purple loosestrife grows 3.0-10.0 ft (1-3 m) tall, with an average height of 5 ft (1.5 m). Established plants have 30 to 50 shoots that form wide-topped crowns and dominate the herbaceous canopy.
Purple loosestrife grows 3.0-10.0 ft (1-3 m) tall, with an average height of 5 ft (1.5 m). Established plants have 30 to 50 shoots that form wide-topped crowns and dominate the herbaceous canopy.
Flower |
Leaves & Stock |
Seeds |
Rootstock |
Individual flowers have five or six pink-purple petals surrounding small, yellow centers. Each flower spike is made up of many individual flowers. |
Leaves are downy, with smooth edges. They are usually arranged opposite each other in pairs which alternate down the stalk at 90 degree angles, however, they may appear in groups of three. Stalks are square, five or six-sided, woody, as tall as 2 meters (over 6 feet) with several stalks on mature plants. |
As flowers begin to drop off, capsules containing many tiny seeds appear in their place. Depending on where you live, plants may go to seed as early as late July. Each mature plant can produce up to 2.7 million seeds annually. As tiny as grains of sand, seeds are easily spread by water, wind, wildlife and humans. Germination can occur the following season, but seeds may lay dormant for several years before sprouting. |
On mature plants, rootstocks are extensive and can send out up to 30 to 50 shoots, creating a dense web which chokes out other plant life. |
Mechanical Methods
Infestations less than 100 plants can be controlled by pulling or cutting just before the plants begin flowering to avoid spreading seed. When pulling, all root fragments should be removed and plants should be properly disposed of.
Mowing is not recommended because it will spread plant segments and seeds.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Purple Loosestrife and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
Cut-stem Treatment: apply a solution of 30% glyphosate (Rodeo®) to the raw area of freshly cut stems, after the flowering portion has been removed.
Foliar treatment: spot treatment with glyphosate (Rodeo®) is effective on older plants. It is most effective when applied as plants are preparing for dormancy, but mid-summer and late-season treatments may be needed to reduce seed production.
NOTES:
Infestations less than 100 plants can be controlled by pulling or cutting just before the plants begin flowering to avoid spreading seed. When pulling, all root fragments should be removed and plants should be properly disposed of.
Mowing is not recommended because it will spread plant segments and seeds.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Purple Loosestrife and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
Cut-stem Treatment: apply a solution of 30% glyphosate (Rodeo®) to the raw area of freshly cut stems, after the flowering portion has been removed.
Foliar treatment: spot treatment with glyphosate (Rodeo®) is effective on older plants. It is most effective when applied as plants are preparing for dormancy, but mid-summer and late-season treatments may be needed to reduce seed production.
NOTES:
- Mention of particular products in this fact sheet is not intended as an endorsement of the product by the MLWA.
- A DNR permit is required to spray herbicides in public waters and protected wetlands in Minnesota. Contact the Meadow Lake Watershed Association Board for assistance in treating invasive species by chemical methods.
Purple Loosestrife has several look-alikes that may be present on Meadow Lake. Shown below are some of these species.
Links to additional information will be updated periodically
Reed Canary Grass is a major threat to natural wetlands. It out competes most native species. It presents a major challenge in wetland mitigation efforts. It forms large, single-species stands, with which other species cannot compete.
Reed Canary Grass is a perennial coarse, cool-season grass that grows 2-6 ft (0.6-1.8 m) high. It had been especially selected for its vigor, and is one of the first to sprout in spring. It has erect hairless stems.
Reed Canary Grass is a perennial coarse, cool-season grass that grows 2-6 ft (0.6-1.8 m) high. It had been especially selected for its vigor, and is one of the first to sprout in spring. It has erect hairless stems.
Flowers |
Leaves & Stock |
Seeds |
Roots |
Densely clustered single florets that are green to purple when in bloom (May to mid-June) and turn golden tan as seeds form. The flower branches spread during bloom but draw close to the stem at maturity. |
Blades are flat and have a rough texture on both surfaces. Leaf blades gradually taper from the base to the tip and are up to 10 inches long and about ½ inch wide. Top leaves are horizontal. It has a highly transparent ligule (a membrane where blade and sheath meet) and is unusually large—up to ½ inch long. |
The seeds ripen in late June. Seeds can germinate immediately at maturation. Dispersed via waterways, animals, humans, and machines. |
Reproduces vegetatively through horizontal stems growing below the soil surface, called rhizomes, creating a thick impenetrable mat at or directly below the soil surface. |
Mechanical Methods
Burning: Spring burning may increase Reed Canary Grass. Spring burning removes Reed Canary Grass thatch or litter and increases the amount of sunlight reaching the soil surface, which in turn increases both germination of seeds and production of new shoots by rhizomes. For these reasons, spring burns increase the shoot density of reed Canary Grass. Some managers have suggested that germination of seeds following spring burns might reduce the numbers of Reed Canary Grass seeds in the soil. No evidence of such an effect has been found by current research on this question.
Burning is not required for complete coverage of the plant with herbicide. Glyphosate can move throughout the entire plant even if the plant is only partially covered with herbicide. Burning, therefore, does not increase the effectiveness of a subsequent herbicide application.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Reed Canary Grass and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
When standing water is present, use products approved for aquatic use, like Rodeo. When standing water is not present, use other products, like Roundup. Follow specifications for perennial weeds on the label to determine application rate and concentration. Apply glyphosate late in the season during August or September when the leaves will take it to the roots to achieve maximum control. Early applications also may be effective against seedlings up to two weeks after emergence.
Plan for multiple years of control. Even if an application of glyphosate kills both the above ground shoots and rhizomes the of Reed Canary Grass present at a site, it is likely that the plant will re-colonize through germination from the seedbank. Therefore, continued spot-treatment with herbicide or hand pulling of newly established Reed Canary Grass plants will be needed at most sites.
NOTES:
Burning: Spring burning may increase Reed Canary Grass. Spring burning removes Reed Canary Grass thatch or litter and increases the amount of sunlight reaching the soil surface, which in turn increases both germination of seeds and production of new shoots by rhizomes. For these reasons, spring burns increase the shoot density of reed Canary Grass. Some managers have suggested that germination of seeds following spring burns might reduce the numbers of Reed Canary Grass seeds in the soil. No evidence of such an effect has been found by current research on this question.
Burning is not required for complete coverage of the plant with herbicide. Glyphosate can move throughout the entire plant even if the plant is only partially covered with herbicide. Burning, therefore, does not increase the effectiveness of a subsequent herbicide application.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Reed Canary Grass and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
When standing water is present, use products approved for aquatic use, like Rodeo. When standing water is not present, use other products, like Roundup. Follow specifications for perennial weeds on the label to determine application rate and concentration. Apply glyphosate late in the season during August or September when the leaves will take it to the roots to achieve maximum control. Early applications also may be effective against seedlings up to two weeks after emergence.
Plan for multiple years of control. Even if an application of glyphosate kills both the above ground shoots and rhizomes the of Reed Canary Grass present at a site, it is likely that the plant will re-colonize through germination from the seedbank. Therefore, continued spot-treatment with herbicide or hand pulling of newly established Reed Canary Grass plants will be needed at most sites.
NOTES:
- Mention of particular products in this fact sheet is not intended as an endorsement of the product by the MLWA.
- A DNR permit is required to spray herbicides in public waters and protected wetlands in Minnesota. Contact the Meadow Lake Watershed Association Board for assistance in treating invasive species by chemical methods.
Links to additional information will be updated periodically
Links to additional information will be updated periodically
Yellow Flag Iris is a wetland plant that is especially showy during its short blooming period. This good-looking plant has been transplanted into well-watered gardens all over the world and has widely escaped. Like cat-tails, yellow iris colonizes into large numbers, forming very dense monotypic stands, out-competing other plants. The plant also blocks water flow and damages bird nesting sites and important fish habitat.
Perennial aquatic herbaceous plant, grows 2.0-4.0 ft (0.6-1.2 m) tall along shores in shallow water.
Perennial aquatic herbaceous plant, grows 2.0-4.0 ft (0.6-1.2 m) tall along shores in shallow water.
Flowers |
Leaves & Stock |
Seeds |
Rootstock |
Showy and variable in color from almost white to a vibrant dark yellow. Flowers are between 3-4 inches wide and bloom from April to June. Three upright petals are less showy than the larger three downward pointing sepals, which may have brown to purple colored streaks. |
Broad, sword-shaped leaves grow upright, tall and stiff. They are green with a slight blue-grey tint and are very difficult to distinguish from other ornamental or native iris species. Flowers are produced on a stem that can grow 3-4 feet tall amongst leaves that are usually as tall or taller. |
Seeds are produced in fruits that are 6-angled capsules, 2-4 inches long. Each fruit may have over 100 seeds that start pale before turning dark brown. Each seed has a hard outer casing with a small air space underneath, which allows the seeds to float. |
Thick, fleshy pink-colored rhizomes spread extensively in good conditions, forming thick mats that can float on the surface of water. |
Mechanical Methods
If pulling or digging Yellow Flag Iris, care should be used to protect the skin as resins in the leaves and rhizomes can cause irritation. Because rhizome fragments can grow to form new plants, all rhizome fragments must be carefully removed.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Yellow Flag Iris and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
Cut-stem Treatment: It is best to cut the stems off, dispose of them properly, then apply the appropriate herbicide to the stump. Apply a solution of 30% glyphosate (Rodeo®) to the raw area of freshly cut stems.
NOTES:
If pulling or digging Yellow Flag Iris, care should be used to protect the skin as resins in the leaves and rhizomes can cause irritation. Because rhizome fragments can grow to form new plants, all rhizome fragments must be carefully removed.
Chemical Methods
Glyphosate, the active ingredient in Monsanto’s Rodeo® and Roundup® products, is the most commonly used herbicide to treat Yellow Flag Iris and can be very effective. The herbicide is non-selective, so it needs to be applied only to the target area. Glyphosate has low toxicity to animals.
Cut-stem Treatment: It is best to cut the stems off, dispose of them properly, then apply the appropriate herbicide to the stump. Apply a solution of 30% glyphosate (Rodeo®) to the raw area of freshly cut stems.
NOTES:
- Mention of particular products in this fact sheet is not intended as an endorsement of the product by the MLWA.
- A DNR permit is required to spray herbicides in public waters and protected wetlands in Minnesota. Contact the Meadow Lake Watershed Association Board for assistance in treating invasive species by chemical methods.
Links to additional information will be updated periodically
Links to additional information will be updated periodically
