What most people think of as "weeds" are really bandage plants. They're designed to seek out disturbed soil and cover it as quickly as possible so it doesn't erode. There are whole ecosystems specialized to take over after a fire, a flood, a landslide, and so on. That's their job.

Ironically, it reveals a branch of weed control that modern people don't seem to think of: kill it with kindness. A bag of compost and one of topsoil will make the earth too rich; a strip of healthy sod is impossible for many weeds to compete with.