Tuesday, May 02, 2006



Three pictures of wisteria, taken earlier today. You don't often see it growing in Portland, although it grows perfectly well here. When I lived in the deep south, the stuff grew like a weed. Which is kind of a problem, actually: Some wisteria species are native to eastern North America, and others are nonnative imports from Japan and China. This page from the National Park Service describes the nonnative wisterias as aggressive, invasive species that can crowd out native plants and strangle trees. Which is true, and alarming, and it's clearly a bad thing, of course. But it's also an awfully photogenic invasion, you have to admit. And all the intensive herbicide campaigns in the world won't do any good if people keep buying the stuff at their local nursery and planting it everywhere.


The invasive species that keeps people (well, certain people) up at night in the Portland area is English Ivy, which is just as aggressive, and also doesn't have flowers. A local group called the No Ivy League has been campaigning against the stuff for 10 years now. It's too early to say who's winning. They'd probably hate my neighborhood, where the public spaces are planted almost exclusively in ivy. I'm not sure what sort of ivy, but the landscaping was first done in the 60's, and they probably used whatever species seemed hardiest, which probably means it's the bad kind.


And let's not even get started about kudzu...

Updated: Ahh, how could I have forgotten our other local invasive vine, the Himalayan blackberry, not to be confused with the various native blackberries and related Rubus species native to the Northwest. And also not to be confused with the region's commercially cultivated varieties.

Last summer a fungal condition called Phragmidium Rust Disease was detected in the state for the first time, and it apparently attacks only the Himalayan blackberry and one cultivated species. So on one hand, there might now be something to check the spread of nonnative blackberries, but the "cure" seems to be yet another nonnative organism. Oh, lucky us.

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