The overwhelming colour and density of spiked flowers blanketing many of Canada's finest wetlands are contrasted by an unnatural stillness. The silence in these usually vibrant environments pulls at your ears, telling you something is terribly wrong.
You no longer see the muskrat family and their ripples on the water. You don't hear the familiar slap of the beaver tail. The multitudes of native songbird species are reduced to a handful. Deer that once frequented the marsh edge had disappeared, along with raccoons, waterfowl, shorebirds, and painted turtles that once shared this habitat.
Fishing is out of the question now. You can't hear or touch the water because the thick plant growth below and above the surface stops you from penetrating more than a few steps into the wetland. Native sedges, bulrushes, and grasses are gone, as are the original floating and submerged aquatic vegetation.
If you have been visiting this spot for five to ten years, you realize the death of this wetland had been gradual. It didn't happen overnight. What careless act destroyed these once rich and diversified biosystems?
There really is no mystery. The killer is purple loosestrife (Lythrum salicaria), a hardy flowering plant that was accidentally introduced to North America from Europe in the 1800's. Since then, purple loosestrife has made a slow, relentless invasion of wetlands and waterways, primarily in Eastern Canada, but also in British Columbia.
In other parts of Canada, particularly the Prairies, the spread occurred as seeds from innocently planted home landscape specimens found their way into adjacent water bodies. Because this beautiful killer has no natural enemy in North America, purple loosestrife has expanded its range into every Canadian province. It is spreading at an alarming rate and can now be found from coast to coast.
But purple loosestrife is an attractive plant. It's vigorous and durable. We plant it once and it seems to last forever. Nothing hurts it. Why should we be concerned?
We should be concerned because nothing hurts it. The plant takes over ponds, beaches, marshes, stream banks, farm dugouts, irrigation and navigation canals, lakeshores, and ditches. It can even take over effluent purification ponds! Any shallow water body that can support life is susceptible to infestation and domination by purple loosestrife. Any water body that receives even one seed may eventually become totally choked out by this weed.
Once a wetland is overrun with loosestrife, the natural habitat is lost and the productivity of native plant and animal communities severely reduced. Nearby water bodies are also likely to be affected by this or other types of habitat destruction. There is no room for displaced wildlife. Fish and invertebrate populations that cannot move are lost forever. The loss of wildlife habitat caused by this plant scourge is enormous.
Height: 3 to 6 feet (1 to 2 meters)
Stalk: square, woody, several stalks per plant
Leaves: smooth edges, opposite side of the stalk, attached directly to the stalk
Flowers: long pink/purple spike, June to September
Purple loosestrife manages to colonize and thrive so easily because of its prolific seed production. Each plant can produce up to 2.7 million seed in one season. Seeds are carried far and wide by birds, animals, water or the wind and can remain viable for many years.
Purple loosestrife is a highly competitive plant from the moment a seed touches the mud. It germinates quicker and grows faster than just about any other Canadian wetland species. It quickly trap nutrients and sunlight to establish tall adult plants.
In the wild, organisms that compete the best will prosper...the law of nature...survival of the fittest. Purple loosestrife is the top competitor! The infested water system eventually becomes choked with the invading plant. Open water becomes a solid mass of woody stalks. Even the soft, muddy floor of wetland becomes a woven mat of tough roots with no significant value for other organisms.
There is no Canadian bird, animal or fish that depends on any part of this plant. That means wetland creatures eat around purple loosestrife, consuming the remaining native plant population. They effectively "eat themselves out of house and home!" As native vegetation is consumed, more space is created for the new purple loosestrife plants.
Control measures such as burning, mowing and flooding have met with little success. Environmentally acceptable control measures are being sought by federal and provincial governments, universities and private organizations. This research is currently underway in Canada and the United States, but the prospects are not good for an immediate solution. no biological controls have been approved, nor are there any chemicals registered in Canada for the purple loosestrife eradication.
The best course of action currently available is to stop the spread. We must all work together to prevent further plantings and natural spread. If we don't stop purple loosestrife now, the economic burden to taxpayers will only increase as our vital waterways and wetlands become choked with this plant.
The challenge before us is how do we get rid of the billions of purple loosestrife plants already growing on the continent? Eradication by pulling plants by the roots can be effective on the small scale, but pulling is not viable where large infestations occur. In local planting and flower gardens, you can do your part by pulling and burning any plant, root and seed material. You can help your friends and neighbours do the same. Discourage any and all new purple loosestrife plantings! Check with your local nursery or horticultural organization for information on alternate species.
Before a more intensive Canada-wide control program can be designed, better information on infested areas is required. The location and severity of each and every purple loosestrife site should be reported. This will allow fast action once eradication measure are available. If you know of purple loosestrife outbreaks, use the report in this brochure. With everyone's cooperation, we can turn back this threat to our precious wetland resource.
For more information on purple loosestrife in your area, contact Ducks Unlimited or the Canadian Wildlife Service, or forward your request to the Canadian Wildlife Federation in Ottawa.