SPOTTED KNAPWOOD SPOTTED

Funny how sometimes you think you are seeing everything clearly, but you're really not. You're missing important details. Take noxious weeds for instance. Often they are growing right beside you, but you don't even notice them until they are going to seed, and by then it's too late to deal with them.

This happened to me recently on my morning walk down the dirt road behind our house. I'm pretty keyed in to the hoary alyssum, sulfur cinquefoil, common tansy, ox-eye daisy, and Canada thistle, and will stop and pull what I can if the patch is small. This year, the spotted knapweed snuck up on me, growing undetected amongst the tall grass bordering our field. Just a few days ago, the plants began to flower. Their pinkish-purple color is pretty, but my reaction was anything but appreciative! Horrified, disgusted, and angry are better words to describe how I felt. Angry because it's a lot of work to remove big patches of knapweed by hand.

Here's what the Montana State University extension bulletin says about spotted knapweed: "Spotted knapweed blooms from mid- to late July through early September. Individual flower heads bloom for two to six days before the bracts close. Bracts reopen after about 20 days, and seeds are dispersed by physical movement of the plant. The weed is a prolific producer with 1000 or more seeds per plant. Seeds remain viable in soil for more than eight years and are spread easily by water, animals, humans, and vehicles."

What to do?

The MSU extension advises:

• A single, low-intensity fire does not control knapweed.

• Cultivation to depths of 7 inches or more will control spotted knapweed, but the weeds can regenerate from seeds remaining in the sail.

• Grazing cattle, sheep, and goats will reduce levels of knapweed, but first-year plants are too low to the ground for easy grazing, and mature plants are fibrous and coarse and not an animal's first choice.

• Hand pulling can be effective and is most easily done after a rain. Flowering plants must be contained, removed, and disposed of in a way that doesn't allow the seeds to disperse.

• Mowing during late bud stage can reduce the number of seeds produced.

• If revegetation is your strategy, it "...usually involves a spring or early summer application of Tordon 22K, Transline or Curtail followed by a dormant seeding of grass in late fall."

What did I do? I pulled the plants I could, but the largest wouldn't come out, and I didn't have time to wait for rain. So I cut them close to the ground, transported in a cart to the burn pile, and covered them with a tarp until dry enough to burn.

The problem, as one weed service told me years ago, is that there are so many seeds in the so-called "seed bank" that it takes at least three years of careful management to eradicate nasty noxious weeds.

Today, as I wheeled my knapweed-laden cart down the road, the air filled with the white fluffy seeds of Canada thistle blowing hither and yon. It's enough to make you feel puny and ineffective, because noxious weed manage really is everyone's problem and everyone's responsibility.

—Dan Spurr