Tuesday, August 28, 2012


Photo: Caroline Savage, Env Canada

Last summer we celebrated a friend's eightieth birthday by cruising along the Fraser in a riverboat. Curious about the gorgeous purple flowers that covered the small islands we passed, I asked someone what they were.

The answer was purple loosestrife. Native to Eurasia, in North America this plant is an invasive species. Among its epithets are marsh monster and beautiful killer.

This moisture-loving plant can quickly clog ditches, and in agricultural areas, it interferes with water flow through irrigation systems, and makes fodder less valuable. It is very hard to eradicate, as it can regenerate from roots as well as producing seeds with an almost perfect germination rate.

Individual plants grow up to two metres tall. Because it grows in wetlands, herbicides cannot be used against it. Amazingly, biological control takes the form of certain legally approved beetles and weevils that eat the plant and attack its roots and seeds, without damaging other plants.

Yet several varieties of this lovely-looking plant are grown in gardens. According to the Manitoba Purple Loosestrife Project, "garden escapes" lead to infestations: this tough and resilient plant quickly takes over, pushing out native species. Reduced biodiversity has deleterious effects on nutrient recycling and wildlife.

Oddly enough, loosestrife can be beneficial as well as being pesky. Thought to have come to North America on European ships in the early 1800s, it is believed by some to have been brought as a medicinal herb used to treat ulcers and dysentery. According to Botanical Online, the plant also combats skin diseases and conjunctivitis.

This plant's odd name is indeed derived from the Greek words for to loose, and strife. But how and why this plant came to be named this way is something I have been unable to discover.

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