Alex Normile, age 14, Arlington, Mass

What are tumbleweeds?

Whoever heard of plants going for a stroll? The tumbleweed does, come late summer, it rolls and bowls before the wind over the plains and the prairies, Surely this bundle of dry twigs has nowhere special to go, Not at all. The tumbling tumbleweed is on a very important mission, It‑is a parent plant scattering its seeds:

All plants do the best they can to give their‑seeds a good start in life: To avoid overcrowding, the seeds should be scattered some distance from the parent plant, There are countless tricks in the plant world for scattering seeds far and wide.

Pea pods become pea shooters. They dry up and split open with a sudden pop. The jerk sends the ripe seeds flying in all directions through the air. The elm tree and the dandelion rely on the breezes to scatter their seeds, The ripe elm seeds drift away from home on gliding wings. The dandelion launches its seeds on feathery parachutes, Burdock and cocklebur depend on passing animals. Their seeds have hooks for clinging to furry coats. The coconut often drops a big seed in the water to be floated to some friendly shore,

The tumbleweed goes to far more trouble to scatter its seed, As the seeds ripen, the= green leaves dry up and blow away, The twigs and stalks become dry and brittle, The plant waits for a strong gust of wind, Suddenly the stem snaps off close to the ground, The tumbleweed is ready to stroll along ahead of the wind.

The breezes blow through the light dry twigs  lifting and rolling the round bushy plant over the ground, It is bounced, bumped and shaken as it goes tumbling along. This is what it needs, for the dry seeds are scattered far and wide. A number of very different plants use the tumbling method of seed scattering. The large] prickly tumbleweed is the Russian thistle, This nuisance is a native of Europe and a single plant may scatter a million seeds, Witch grass, seeds. Witch grass  also called couch and panic; grass, is another native of Europe. This plant also spreads by growing durable underground rhizomes.

The bug seed and the tumbling pigweed are native American tumblers. The bugseed is named for its flat oval seeds. The tumbling pigweed is the green amaranth. Poets once imagined a flower that never fades. The impossible blossom was named amaranth. The name was borrowed to name certain beautiful cultivated flowers. The green flowered tumbling pigweed happens to belong to the same family.

Let’s not be fooled by fancy names and elegant relatives. All tumbleweeds are pests and a nuisance to the farmer. Like all weeds however  they do serve a purpose in the wild. Their roots bind down loose soil; Their green leaves add oxygen to the air. Finally they decay and add chemical plant food to the soil.