Purple Loosestrife

Purple Loosestrife is one of those flowers that is considered a “Weed” because it is so invasive everywhere it gets established. It is actually a wetland (perennial) herb that grows from 6-8 feet in height. It does best in the following places:

• Sunny wetlands
• Around ponds and ditches
• Wet prairies
• Along streams
• Moist fields and pastures

Purple Loosestrife is a problem because of it’s aggressive growth ability. A single plant can produce up to 300,000 seeds which are distributed by animals, water, and wind. In addition to seeds production, Purple Loosestrife reproduces by cuttings and offshoots as well. It has a persistent tap root and spreading root stock that turns into thick & woody roots as it matures.

This plant is so aggressive that it crowds out native plants that are used as food for wildlife. To make matters worse, it can destroy marshes and wet prairies and completely choke off waterways. This is why control measures must be taken before too much damage has taken place.

Purple Loosestrife was introduced to North America from Europe in the early 1800’s in ship ballast. It was also brought in to be used as a medicinal herb as well as a decorative ornamental plant. When you see a field of Purple Loosestrife you’ll admit it is beautiful despite its invasive nature.

No native herbivores or pathogens in North America are known to suppress this plant. Best ways to control Purple Loosestrife is by physically cutting (by hand or mechanically) or by use of herbicides. There is another method that is being looked at that would make use of native control measures. Since this plant is from Europe that’s the natural place to look.

There are insects native to Europe including a root-mining weevil and a leaf-eating beetle that are natural enemies to Purple Loosestrife. Attempts are being made to introduce these to some North American areas to test the results. They both work to kill the plant in these ways:

* The root-mining weevil lays eggs into the stem of the Loosestrife and the developing larvae work their way down into the roots where they feed extensively on the root tissue. Also, the adult weevils feed on newly formed leaves.

* The leaf-eating beetles affect the plant by feeding on the newly formed leafs while their larvae feed on the buds, leaf, and stem tissues.

First of all, it’s a beautiful flowering plant that does come back year after year. Seriously, if you have an area that is barren or flooded a lot this could be an interesting answer if kept under control.

Beekeepers consider the late season flowers of Purple Loosestrife as a good source of nectar and pollen for bees over-wintering. A field full of Purple Loosestrife would guarantee a field full of beneficial bees.

There have been medicinal uses for purple loosestrife that date back to the 1st century. Tonics and potions made from Purple Loosestrife have treated ailments including bleeding (internal & external), healing of wounds & ulcers, and dysentery.