Similar Climate of Origin
  Lack of Natural Enemies
  Prolific Reproduction
  Seed Dispersal
  Fast, Early Growth
  Novel Weapons

Home>What Weeds Do>Weed Tactics>Seed DispersalImage of a seed

Seed Dispersal

Plants cannot move, so they have developed strategies for dispersing their offspring away from the parent plant. Weeds are particularly good at this, and are often among the first to occupy disturbed sites. Seeds, and other plant propagules, can be dispersed by wind, water, animals, and humans.

Woman walking in the windWind dispersal
Bull thistle, Canada thistle, and rush skeletonweed, like the common dandelion, have a fluffy umbrella-like structure that will carry seeds in the wind. Weeds like Russian thistle, halogeton, and diffuse and squarrose knapweed break off at ground level when dry and tumble with the wind, scattering mature seeds.

Picture of a river

Water dispersal
Weeds like perennial pepperweed, which often grows near water, can have seeds and roots that float, enabling long-distance transport in streams and rivers.

Image of horse and manureAnimal dispersal
There are multitudes of ways animals can aide in weed dispersal. Seeds can pass through the digestive tracts of animals, be transported in mud attached to hooves and hide, and sprout from seed caches. Knapweeds seeds and seedheads cling to fur like burrs. The sharp thorns on yellow starthistle seedheads can jab into passing animal hide. Small barbs on cheatgrass and medusahead seeds facilitate being picked up by feathers and fur.Image of weed seeds in socks and shoelaces

Human dispersal
Humans play a big part in seeds dispersal today. Seeds stick into socks, shoes, and other clothing. Vehicles and farm machinery can get seeds and plant parts caught underneath. Transported soil, animal feed, and seed can contain weed propagules. We are particularly adept at weed dispersal because we travel both frequently and over long distances.

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