And when we got back to the bunkhouse near Tower Falls and Hell Roaring Flats, I noticed a chart on the wall I hadn't before with color photos of invasive plants: bull thistle
, spotted knapweed, dalmation toadflax, houndstongue, and leafy spurge.
The leaves are easily distinguished from those of the common or bull thistle
, the leaves of which are very rough on both surfaces and bear a large number of spines of varying lengths.
Yet the grandest of them all, towering up to six feet in height, are the purple bull thistles
, with blue and pink flowers the size of eggs nodding on thin, spine-covered stalks.
The few weeds they don't like, like bull thistles
, you can mow or hoe after you move the animals to the next paddock.
The foresters soon found big "vinelands" in other parks, including Inwood Hill, where we pass a ridgetop meadow of tall grass dotted by purple bull thistles