how to get rid of invasive purple loosetrife naturally? Get expert insights and tips

Purple loosestrife may look beautiful with its tall spikes of purple flowers, but don't be fooled - this invasive plant is a menace. Originally from Europe and Asia, purple loosestrife was brought to North America in the 1800s as an ornamental plant. Without any natural predators to keep it in check, it has spread aggressively across wetlands, crowding out native plants that provide food and shelter for wildlife.

How to Get rid of invasive purple loosestrife naturally can seem daunting, but with persistence and an integrated approach, there are effective natural methods. Biological control using specialized beetles that feed on the plant shows great promise for long-term control.

Manual removal of small infestations before seeds set can eliminate plants and root fragments that sprout new growth. Careful spot treatment with aquatic herbicides containing glyphosate also provides selective control when native plants are interspersed.

An observant eye and quick action are key to stopping purple loosestrife before dense stands establish. With some determination and the right techniques, you can get rid of invasive purple loosestrife naturally and restore balance to your wetlands.

How To Get Rid Of Invasive Purple Loosetrife Naturally

Identifying Purple Loosestrife

Purple loosestrife is a herbaceous perennial that grows 3-7 feet tall on stiff, four-sided stems. It has opposite or whorled leaves that are lance-shaped and heart-shaped at the base. From July to September, dense spikes of purple-magenta flowers with 5-7 petals bloom at the tips of its branches.

Purple loosestrife can be confused with similar native plants like winged loosestrife (Lythrum alatum), which has a winged stem, and swamp loosestrife (Decodon verticillatus), which has a rounded stem. Examining the stem shape is key to correctly identifying purple loosestrife.

This invasive plant thrives in disturbed wetlands, lakeshores, riverbanks, and ditches. It can quickly form dense stands that crowd out native grasses, sedges, and other flowering plants that are important food sources for pollinators and wildlife.

Impacts on Ecosystems

Once established, purple loosestrife outcompetes native vegetation and reduces biodiversity. As it spreads, it can clog irrigation canals, degrade farmland, and inhibit the reforestation of wetlands.

By crowding out native plants, purple loosestrife reduces food sources and habitat for many wetland animals. Declines have been noted in bird populations of special concern like the black tern, as well as ducks, geese, and songbirds that rely on native wetland vegetation.

In addition, the decomposition of purple loosestrife leaf litter releases chemicals that may inhibit the growth of other plants. The plant can also change wetland hydrology by trapping sediments and restricting water flow.

  • Purple loosestrife is an invasive wetland plant native to Europe and Asia that has spread aggressively across North America. It outcompetes and displaces native plants, reducing biodiversity.
  • Dense stands of purple loosestrife eliminate open water habitat needed by waterfowl, amphibians, and other wildlife. It provides little food or shelter for native wildlife compared to the diverse native plants it displaces.
  • Purple loosestrife can clog irrigation canals, degrade farmland, reduce the forage value of pastures, and impede boat travel, impacting agriculture and recreation.
  • The plant's fast growth and prolific seed production allow it to spread rapidly. A single plant can produce over 2 million seeds per year. Seeds spread easily by wind, water, animals, and human activities.
  • Purple loosestrife alters wetland hydrology and chemistry. It changes decomposition and nutrient cycling rates compared to native plants, affecting ecosystem function.
  • Conventional control methods like digging up plants are ineffective at stopping their spread due to the vast seed bank. Biological control using specialized beetles that only feed on purple loosestrife has been the most effective long-term control method.

Purple loosestrife is an aggressive invader that has significant detrimental ecological and economic impacts in wetlands across North America. Controlling its spread is important to protect native biodiversity and ecosystem health.

Manual Removal Methods

Small infestations of purple loosestrife can be effectively removed through manual techniques like hand pulling, digging, and cutting/mowing. The key is to eliminate the entire root system, as any left behind can resprout new plants.

Hand Pulling

For young plants under 2 years old, hand pulling is straightforward. Grasp the base of the plant and pull straight up, removing all roots and stems.


Use a spade or garden fork to dig up larger, older plants. Try to extract as much of the root system as possible, as broken root sections may regenerate into new plants.


In areas with extensive purple loosestrife, mowing or cutting plants can help curb seed spread. Cut stems at ground level before seeds set in mid-summer. Repeat cutting may be needed to weaken the plants' root reserves.

Proper Disposal

After manual removal, dry out pulled plants and roots then burn or bag for landfill disposal. Never compost purple loosestrife, as seeds may still be viable.

Biological Control

For large infestations, biological control using natural insect predators can provide long-term suppression. Several species of loosestrife beetles from Europe have been approved for biocontrol programs in North America. Different beetle species target either leaves, stems, roots, or flower heads of purple loosestrife. Adult beetles feed on leaves and stems, while larvae bore inside roots and stems to feed.

This damages and stresses the plants, slowing growth and seed output over time. However, complete eradication is unlikely. Contact your local agriculture extension office to obtain loosestrife beetles for release. Ideal times are early spring and late summer when plants are small. Monitor sites and replenish beetle populations annually as needed. Other biological controls are still under evaluation.

Prevention and Maintenance

How To Get Rid Of Purple Loosetrife Naturally

Preventing purple loosestrife from initially establishing will make control much easier.

  • Scout for new seedlings each spring and remove them before roots become established.
  • Clean equipment, footwear, and boats/trailers after use in infested areas to avoid further spread.
  • Encourage neighbors to remove purple loosestrife from gardens and dispose of it properly.
  • Advocate locally to stop the sale of purple loosestrife as an ornamental plant.
  • Support restoration of native wetland vegetation to resist purple loosestrife invasion.

With persistence and multiple control methods, it is possible to reduce purple loosestrife to manageable levels. However, continued monitoring and maintenance will be needed to protect ecosystems from this aggressive invader.

Here are some additional tips for getting rid of invasive purple loosestrife naturally:

  • Minimize disturbance to avoid creating opportunities for seed germination. Purple loosestrife spreads rapidly by seeds, so avoid disturbing the soil where it grows.
  • Properly dispose of all parts of the plant. Put plant pieces and roots in plastic bags and dispose of in a landfill, not a compost pile. Or dry out the plants completely and burn if allowed. This prevents seeds from spreading.
  • Use biological control agents like leaf-eating beetles that feed on purple loosestrife. Contact your state department of Natural Resources to obtain beetles for release in infested wetlands. The beetles can reduce loosestrife density so native plants can better compete.
  • For small infestations, hand-pull plants before seeds set in mid-summer. Remove all root fragments so no new plants sprout. Use a garden fork for larger roots.
  • Spot treat individual plants with herbicide like glyphosate or triclopyr. Avoid broadcast spraying which opens areas for loosestrife seeds to germinate. Always follow herbicide regulations and permitting.
  • Plant native species to compete with loosestrife. Choose native plants adapted for the wetland habitat purple loosestrife invades.
  • Educate others not to purchase or plant purple loosestrife. Ask nurseries and garden centers not to sell it.
  • Report infestations early and contain initial spread by monitoring edges and removing new growth. Focus control efforts on small populations first before they expand.
  • Combining control methods like biological control, herbicide spot treatment, and hand pulling often provides the best long-term management of invasive purple loosestrife.

What are some native species that are affected by purple loosestrife?

Some native species that are negatively affected by purple loosestrife include:

  • Marsh wrens: Purple loosestrife reduces habitat for marsh wrens by replacing cattails that the birds use for nesting with its own shrubby structure. Marsh wren populations decline where purple loosestrife dominates
  • Least bitterns: Like marsh wrens, least bitterns nest in cattail marshes, which are threatened by purple loosestrife. Loss of nesting habitat further endangers this threatened bird species.
  • Cattail sedge: An endangered plant species in New York, cattail sedge shares wetland habitat with purple loosestrife and is at risk of being outcompeted.
  • Cardinal flower: A showy wetland plant, the cardinal flower is one of many native species crowded out by dense purple loosestrife stands. This reduces biodiversity in wetlands
  • Amphibians: By changing wetland hydrology and reducing habitat, purple loosestrife negatively impacts amphibian breeding
  • Mammals: Species like muskrat and beaver that utilize cattail marshes are displaced as purple loosestrife takes over.
  • Insects: Purple loosestrife flowers provide little food for native insects compared to diverse native plants. This reduces resources for insects and animals that feed on them.

What are some alternative native plant species that can be used to replace purple loosestrife in wetland habitats?

Here are some good native plant alternatives that can replace purple loosestrife in wetland habitats: The key is to choose native plants adapted to the wetland conditions in your area. They will provide food and habitat for local wildlife while avoiding the invasiveness of non-native purple loosestrife.

  • Joe Pye weed (Eutrochium spp.) - Large clusters of pinkish-purple flowers. Butterfly nectar source. Tolerates moist soils.
  • Ironweed (Vernonia noveboracensis) - Tall purple flower clusters. Good for butterflies. Wetland tolerant.
  • Cardinal flower (Lobelia cardinalis) - Brilliant red flowers on tall spikes. Hummingbird magnet. Tolerates soggy soils.
  • Swamp rose (Rosa palustris) - Showy pink flowers. Provides good cover and food for birds. Wetland tolerant.
  • Great blue lobelia (Lobelia siphilitica) - Tall blue flowers on leafy spikes. Grows in wetlands. Attracts hummingbirds and butterflies.
  • Blue vervain (Verbena hastata) - Spikes of bluish-purple flowers. Grows in wet meadows, marshes, and along streambanks.
  • Swamp milkweed (Asclepias incarnata) - Pink flowers. Host plant for monarch butterflies. Tolerates wet soils.
  • Blazing star (Liatris spp.) - Showy, purple flower spikes. Grows well in wet areas. Good for butterflies and bees.

Frequently Asked Questions: How to Get Rid of Invasive Purple Loosestrife Naturally

Q1: What is purple loosestrife?

Purple loosestrife (Lythrum salicaria) is an invasive plant species that can cause significant damage to wetlands and native habitats. It grows tall with spikes of purple flowers, taking over areas where native plants should be thriving.

Q2: How does purple loosestrife spread?

Purple loosestrife spreads through its root system and by producing millions of seeds. These seeds can easily spread and establish new plants in moist areas, creating dense stands that outcompete native vegetation and disrupt wildlife habitat.

Q3: Why is it important to control purple loosestrife?

Purple loosestrife is considered an invasive species because of its ability to take over wetland habitats. Its rapid growth and dense stands can harm native plants, reduce biodiversity, and negatively impact wildlife populations. Controlling purple loosestrife is essential for preserving the ecological balance of wetland ecosystems.

Q4: Are there any natural control methods for purple loosestrife?

Yes, there are natural control methods for purple loosestrife. One effective method is biological control, which involves introducing specific insects, such as beetles, that feed on purple loosestrife and help reduce its population. This approach is often used in conjunction with other control methods.Q5: What are the different control method

Q5: What are the different control methods for purple loosestrife?

Control methods for purple loosestrife include biological control, manual removal, and chemical control. Biological control involves using insects or other animals to naturally reduce the population. Manual removal includes pulling or cutting the plants, especially before they flower and produce seeds. Chemical control involves the use of approved herbicides specifically designed to target and eliminate purple loosestrife.

Q6: Do I need a permit to control purple loosestrife?

This requirement may vary depending on your location. It is advisable to check with your local Department of Natural Resources (DNR) or relevant authority to determine whether a permit is required for controlling purple loosestrife.


Purple loosestrife can degrade wetlands and waterways by displacing native plants important to wildlife. Using techniques like hand pulling, digging, cutting, and biological control can remove and suppress infestations without chemicals. With proper identification, disposal, and prevention, we can help keep purple loosestrife in check and restore biodiversity to our wetlands.