Purple Loosestrife
Management Prioritization
Identification
Common Name: Purple Loosestrife
Scientific Name: Lythrum salicaria L.
Legal Status: Prohibited - Control
Efforts must be made to prevent seed maturation and dispersal of plants into new areas. Additionally, no transportation, propagation, or sale of these plants is allowed. Failure to comply may result in enforcement action by the county or local municipality. Minnesota Noxious Weed Law .
Background
Purple loosestrife is native to Europe and Asia. It was introduced to North America in the early 1800s in ship ballast and as a medicinal herb. It is now found in 40 US states.
Purple loosestrife is a semi-aquatic perennial species that typically forms a dense bushy growth of many erect stems reaching heights of approximately 4- 7 feet tall.
Stem
Purple loosestrife has a square stem, which is generally four to six-sided. A single plant is made up of multiple woody stems.
Purple loosestrife has a stem with 4-6 flat sides
Purple loosestrife with multiple stems coming from roots
Leaves
Leaves are smooth-edged, slender, pointed and arranged in opposite pairs along ridged stems.
Purple loosestrife leaves
Flower
Showy spikes of flowers develop at the tops of each stem consisting of many individual 5- 7 petaled purple flowers. It is highly visible from July through September because of its robust purple flowering spikes.
Close up of purple loosestrife flowers
Purple loosestrife seeds and mature seed pod
Roots
Large roots develop over time and store high levels of nutrients providing the plant with reserves of energy early in the spring or during stressful periods.
Mature root crown
Young plant with root
Seedling
Purple loosestrife is a perennial and new stems emerge each year from the root crown.
Purple loosestrife seedling
Distribution
Current Distribution Model
- Point data collected from EDDMapS; not all locations in the state have been recorded, but points on distribution map have been reported and verified.
- Distribution model takes location data and environmental factors into account to create a prediction of current distribution
Management Prioritization
Influenced by:
- distribution models
- actual reports
- economic benefits
- land cover
- conservation features
- trails
High priority areas surround areas of high density to prevent further large infestations and loss of biodiversity.
Infestation Examples
01 / 03
1
General Infested Area
2
Leading Edge
Sparse populations in the transition from infested areas to un-infested areas
Management is involved but can prevent further spread or large establishment of stands.
3
Isolated Population
Location far from other known populations.
Management here is efficient and cost effective.
Lifecycle: Treatment Timing
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). The Trust Fund is a permanent fund constitutionally established by the citizens of Minnesota to assist in the protection, conservation, preservation, and enhancement of the state’s air, water, land, fish, wildlife, and other natural resources. Currently 40% of net Minnesota State Lottery proceeds are dedicated to growing the Trust Fund and ensuring future benefits for Minnesota’s environment and natural resources.
