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Purple Loosestrife
Danger in Disguise

"A beautiful purple menace
invading our wetlands, fields & yards"


How can this seemingly harmless plant with pretty purple flowers be dangerous?

Purple loosestrife's beauty is deceptive. It is an aggressive, non-native flowering plant that is now destroying wetlands and fields across the country, and here in our own backyard!

Destroys wildlife habitat
Once it spreads to a new area, purple loosestrife quickly takes over wetlands, crowding out native plants that provide food and shelter for wildlife such as ducks, turtles, fish and other animals, and destroying fish spawning grounds.

Interferes with recreation
Purple loosestrife literally clogs ponds and rivers. Activities around water diminish. Whether you enjoy boating, swimming, fishing, duck hunting or bird and wildlife watching, your fun can be spoiled.  Communities which depend on local tourism and recreation can lose precious revenue.

Encroaches on crops
Purple loosestrife also invades drier sites. Concern about crops and pastures is increasing in New England as the plant spreads to agricultural land.


Purple loosestrife can be confused with some native  plants.  Look for key characteristics noted below.   Flower spikes bloom from June to September. 


Although eradication of purple loosestrife is almost impossible, its damage can be controlled. The most effective time to take action is before the plant goes to seed.

Cut flower spikes before they develop seeds to prevent this year's seeds from producing more plants. Dispose of seed heads in plastic bags. A mature plant can produce over 2.5 million seeds annually.

Dig the plant from the ground but take care to remove the entire root system as pieces of root will sprout new plants. (A spading fork works well.) This approach works best if there are only a few plants, since purple loosestrife has complex pollination requirements. As with flower spikes, plants should be placed in plastic bags to be incinerated or put in a landfill (not in compost).

Chemical treatment is used when the stands of purple loosestrife are too large for manual control. (Applicators must be licensed to apply chemicals in and around water bodies in N H and VT.)

Biological controls are now being used in this country to fight purple loosestrife. Five insect species which feed exclusively on purple loosestrife in Europe have been approved for use as biocontrol agents in North America. beetles have been  released at several sites
in NH and VT. Beetles are available from N.H. Dept. of Agriculture and VT Dept. of Environmental Conservation.

First line defense:

  • actively & regularly monitor wetlands
  • remove plant at its first appearance.

YOU can make a difference.

What can I do?

As of January 1, 1998, the State of New Hampshire  listed purple loosestrife (Lythrum salicaria) and several other plants as prohibited exotic plants, indicating the serious extent of the invasion of this plant.

Remove purple loosestrife from your property.

Be careful not to confuse it with look-alikes:

  • gayfeather (Liatris spicata)
  • fireweed (Epilobium angustifolium)
  • native loosestrife (Lythrum alatum)
  • and others.
If you are uncertain, contact one of the groups listed in this website to help you.

Don't plant purple loosestrife.

Possible substitutes are:

  • spiked speedwell (Veronica spicata)
  • pink turtlehead (Chelone obliqua)
  • Joe-Pye weed (Eupatorium   fistulosum)
  • queen-of-the-prairie (Filipendula rubra)
  • gayfeather (Liatris spicata)
  • swamp rose mallow (Hibiscus  palustris)
  • purple coneflower (Echinacea  purpurea)
  • bee balm (Monarda didyma).
for more substitue plants see other webpage

Ask your local nursery to stop selling Lythrum cultivars.
Even varieties advertised as sterile can cross-pollinate with purple loosestrife to produce seeds. Inform nurseries of substitutes.

Contact a regional group, for help with control of Purple Loosestrife.