Porcupine Grass – Hesperostipa spartea

Porcupine grass and prairie ragwort

One of the most elegant grasses of the prairie is porcupine grass. Few plants animate wind and light conditions as well as this cool season native. But for all of its grace, few plants cause more pain to the non-observant passerby, particularly when the seed is ripe. Too heavy to be carried far by the wind, this seed spreads by hitching a ride on things in motion. The sharp tip of the seed will pierce and cling to pant legs, shoestrings, exposed socks, as well as the fur and feathers of other prairie users. Now you know the reason for it being called porcupine grass. I also think it is cached by rodents such as the thirteen lined ground squirrel and mice. For years there was a ground squirrel family that harvested the seed in our plots just before I could get to it.

Large, brown, pointed seed with long black awns that will slowly twist and screw the seed into the ground

Last year we were finally able to harvest a pound of seed from our plots. I don’t know where the ground squirrels went: owls? badgers? coyotes? better seed site? The grass shows up in areas where we didn’t plant it making me wonder if some former cache sites have germinated. Here are the particulars:

  • cool season bunch grass growing 1-2′ tall and as wide
  • very slender leaf blades that arch out from the growing point
  • stiff stems that hold the seed head above the plant, gradually drooping towards the ground as the seed ripens and becomes heavier
  • requires full sun to part shade in well-drained soils, will not tolerate wet sites
  • plant 3/4″ deep in the soil in early spring, preferably after 21 days of moist stratification, water if not, or sow fresh seed with the awns intact and the seed will plant itself! Be patient, the seed may not emerge until fall or the following spring.
  • Our seed is dormant, 4% germinated in 21 days of testing at a seed laboratory so it will benefit from cold moist stratification.
  • If you’d like to harvest your own, look for the seed in late June. I pull my hand up the stem and pull the seeds off. They come off easily when ripe. Then immediately cut or break off the long awns. Otherwise the seed will become a ball of tangled, twisting awns.



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