Thistles are a thorny problem for the ag. sector

By Al Lowe
Contributor

What a problem thistles are to the farmer, the rancher, the gardener - just about anybody who has anything to do with agriculture. They are persistent, they grow anywhere, they appear by magic, and most of them have prickles of one kind or another.
And do you know something else about them - most of them are not even native to North America.
The plants which we normally refer to as thistles all have the characteristic head with purplish or pink flowers. They also all have spines. Some spines are tiny and stay under your skin, and some are big as thorns.
These plants spread very, very easily. The seed is very light and is carried on a 'parachute' of fine down. In late summer, thistle down blows all over the place, and finds its way into almost every corner of the land. The down is so easily carried by the wind, that the phrase 'light as thistledown' has become a part of our language.
The Goldfinch, our cheerful little black and yellow 'wild canary' lines its nest with thistledown. It even delays nest building until some of the thistles have gone to seed.
Probably the most persistent thistle of all, and the hardest one to get rid of is the Canada Thistle (Cirsium arvense). In spite of its name, this plant is a native of Europe, where it has been a pest for centuries. It not only spreads by seeds but also by underground roots. These may spread out several feet from the parent plant. If you plough it up, it merely sends out new shoots from the old roots. It can easily fill up a garden or a field in a single season.
There are others, as well. The Welted Thistle, with spined wings on its stem, is another European. So is the Bull Thistle, which may grow to six feet, and the Scotch Thistle, with vicious long spines on its leaves and stem. Some of the native thistles are the Pasture Thistle, with huge three inch flowers, the Field Thistle, which in wet areas will grow to ten feet, and the Tall Thistle, which can grow to twice the height of a man.
Thistles are a real problem. Cattle won't eat them, and they won't eat hay with thistles in. They will crowd out almost every other kind of plant. They can be partially controlled nowadays by spraying, but clean cultivation is still very important for farmers.
Thistles have been mentioned many times in the Bible, so they have been around for a long time. No doubt they will be with us for a long time yet.