Sunday, August 22, 2010

Badly-Behaved Botanical Tourist




A great deal has been written about alien plant species like Japanese knotweed and Himalayan balsam, that have spread into our countryside and proved difficult to control, but inter-continental movement of plant species is two-way traffic and many British wild flowers that are perfectly well behaved here have proved to be devastating invaders when they've been exported overseas. Few have had a greater impact than purple loosestrife Lythrum salicaria, which was introduced into North America in the early 19th. century and has since choked native vegetation in wetlands over a wide area, proving difficult and expensive to control. Here in the UK it's a valued component of the emergent vegetation of wetlands and a desirable plant for a wildlife garden. Back in 1999 a study of 25 wild flower species at Cambridge University Botanic Garden found that it was the best of the bunch for attracting butterflies, and the purple loosestrife in my garden attracts a constant stream of insect visitors like this bumblebee, that was foraging on its flower spikes this afternoon.

6 comments:

  1. Yes... as beautiful as it is along the highway in low, wet places, it is soooo out of control here in the US. I am just beginning to see it pop up on the banks of our swimming hole.. I need to swim to the shallow and slow moving part of the river- and risk the huge leeches - to pull it out before it goes to seed! Thanks for reminding me...

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  2. For once you have posed more questions than answers. Why are some plants despised and others admired? I saw Mare's Tail here on the Tees, not something I've ever noticed in Derbyshire. It was drop dead gorgeous but when I look it up all I get is advice on how to kill it.

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  3. Purple loosestrife is in the process of taking over all our wetlands. last year I saw only isolated stands here and there, but now sone area are carpeted with it. I keep a close eye on the wetland next to our house, and so far nothing - yet.

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  4. Hi Valerianna, Good luck with your efforts to keep it under control. I have some beside my garden pond that spreads a little bit further every year..

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  5. I guess it's a case of right plant, wrong place Adrian...

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  6. Hi Hilke, I've seen photographs of the way it dominates wetlands in the US Hilke ....... I hope it doesn't become a problem in your locality...

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