Repelling an Invasion of Bull Thistle

A little neighborly outreach can go a long ways, especially when the neighbors are forest and river.

It was hard to get me to care about invasive species. After all, up until recently, having a yard in western US suburbia meant importing just about everything – sod, plants, trees, and flowers – and keeping it irrigated to survive in a climate that didn’t really have enough water for that kind of thing. With everyone deliberately bringing in outsiders it seemed pointless to me to go into the neighboring hills to try to weed out invasive species of plants along the hiking trails.

Fast forward to having my own little plot of mountain land which came with very natural (read very sparse) landscaping. Me, and most of my neighbors, are foregoing grass in favor of plants that belong in this habitat and take less water to sustain.

A nice US Forest Service Ranger at one of the town events gave me her booklet on invasive species and asked me to be sure my yard only had native plants so that I wasn’t spreading invasives into nearby Tahoe National Forest and the Truckee River Watershed. I agree, thinking it’d be easy with a natural yard.

Wouldn’t you know, I came back from three weeks in Alaska to find my little postage stamp of land covered in weeds!

Bull_Thistle_over_French_Drain

Most of my weeds turned out to be invasives called Bull Thistle ( or Cirsium Vulagare. Now I probably would have figured out for myself that I don’t want this bad boy in my yard:

Big_Bull_Thistle

What I didn’t know was how to get rid of them without spreading the seeds to my yard and my neighbors – both householders and the National Forest. The Forest Service requests us to Bag and Bake the bull thistle. That procedure entails pulling up all the weeds, getting their flowers and seed pods double-bagged, soaked with soapy water, and left to rot in the sunshine for several weeks. Here’s my bags ready to bake:

invasive_weeds_bagged_to_bake

A few weeks later, on a weed walk sponsored by the Weed Warriors of the Truckee River Watershed Council I was introduced to one of the most noxious invasives of all in our area, the Spotted Knapweed. What makes it so harmful is that it actually puts out a herbicide that kills the plants around it. Spotted knapweed of course is immune to its own secretions and can produce thousands of seeds to take over an area.

Worst of all, something about spotted knapweed looked familiar. Sure enough, what I thought was a friendly flowering weed in my front yard had the tell-tale dark dots on its bracts.

spotted_knapweed_10430_JustinCreekRd
(Photo credit: Andy Seigel)

Like a good citizen I’ve reported the spotted knapweed to the county. If they are able to spray it, fine. If not, I will be looking for professional help for this one.

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