Curly-cup Gumweed
Curly-cup gumweed (Grindelia squarrosa) is a flowering perennial (sometimes a biennial) which can be seen on disturbed sites, on roadsides and trailsides, and on open ground in the grasslands.
- Gumweed grows from a taproot and has a study base for branching stems.
- Toothed leaves grow alternately on the stems.
- The lower leaves may drop in flowering season. The upper leaves tend to be clasping.
- Terminal flower heads have yellow ray and disk flowers.
- Both the leaves and the flowers are resinous.
- All photos by the author. Click an image for a lightbox view.
- Flowers continue to bloom into fall.
- After flowering, achenes form, with a light colored pappus.
- Gumweed is pollinated by several types of bees.
- A similar species has rayless yellow flowers. There are three varieties, each with minor differences.
- Although the plant has been used for medicinal purposes, there are some toxicity issues to be aware of.
- Gumweed is not palatable to livestock so can be a bit problematic for ranchers.
- Gumweed is well-adapted to arid conditions. It is a short-lived perennial, but it reseeds readily on disturbed ground.
- Gumweed can be propated by seed after at least 10 weeks of cold treatment. It is a short-lived perennial, but it reseeds in the same area fairly readily.
- When most of the wildflowers are past, we often see white prairie aster and curly-cup gumweed continue into the first half of fall.