Jill Miller, age 10, of Aurora, Minnesota, for her question:
What is meant by tumbleweeds?
Tumbleweeds are plants and all plants have built in plans to create future plants like themselves. Some sprout runners that anchor new root systems in the soil; others build bulbs that sprout future plants. Most weeds grow from seeds and the parent plants have various fascinating ways to scatter them in new soil. But the tumbleweeds have the most unusual system for sowing their seeds. The parent plants roll and tumble all over the place, scattering seeds as they go.
All summer long, the tumbleweeds grow with the other weeds of the prairies, in fields and vacant lots and along the roadsides. They soak up the golden sunshine, drink in the showers and become bushy balls of fine greenery. Meantime, they grow seeds hundreds of tiny seeds that ripen toward the end of summer. Then the plants wither and lose their greenery. They become big balls of thin, tangled twigs, light enough to be blown away by the breezes.
Come fall, the wind snaps their stems off at ground level. Then the parent plants are all set to travel. The breezes blow them along, rolling and tumbling for miles over the plains and the prairies. They bounce over the ground, shaking loose their seeds and dropping them on the ground. Some seeds will chance to fall on suitable soil. Come spring they sprout roots and become the next generation of tumbleweeds. But most seeds will be eaten by birds and insects who need them for food.
People of the West and the Southwest expect the tumbling tumbleweeds .in the fall and winter. Sometimes hundreds of them pile up against fences, in yards and other places where the big prickly balls of twigs are a nuisance. All these traveling plants are called tumbleweeds, though at least four different weeds scatter their seeds in this fashion.
The biggest one is the Russian thistle big enough to scatter a million seeds. Another tumbleweed type is the couch grass, alias the witch or panic grass. Both these traveling plants originally were natives of Europe. Two other tumbleweeds are native American wild plants. One is the bugseed that strews hundreds of dark oval seeds that look like tiny bugs. The other is the tumbling pigweed, also known as the green amaranth. The pampered garden amaranth has a large bright, long lasting flower. The weedy pigweed has tiny green flowers, but it belongs to the gaudy amaranth plant family
Other plants stay rooted to the spot while they scatter their seeds. The pea plant becomes a pea shooter. Its dry pods split open with a sudden jerk that shoots the ripe seeds off in all directions. The seeds of the dainty dandelion clock have feathery parachutes. They wait for a puff of wind to carry them drifting through the air hoping to land on a suitable patch of soil. The cocklebur hooks its prickly seed package onto furry animals or passing people. But the parent tumbleweeds travel around to scatter their seeds.