INVASIVE PLANTS NEW
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 1-3 m (3.0-10.0 ft) tall, with an average height of 1.5 m (5 ft). Established plants have 30 to 50 shoots that form wide-topped crowns and dominate the herbaceous canopy.
Purple loosestrife grows 1-3 m (3.0-10.0 ft) tall, with an average height of 1.5 m (5 ft). Established plants have 30 to 50 shoots that form wide-topped crowns and dominate the herbaceous canopy.
Flower |
Leaves & Stock |
Seeds |
Rootstock |
|
|
|
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.
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 0.6-1.8 m (2 - 6 ft) 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 0.6-1.8 m (2 - 6 ft) 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
