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U.S. Forest Service

Plant of the Week

Grindelia squarrosa, Western Azalea, range map. Grindelia squarrosa range map. USDA PLANTS Database.

Grindelia squarrosa, curlyleaf gumweed. Grindelia squarrosa is commonly found along roadsides throughout much of the U.S. The copious milky latex on the flower heads is characteristic of this species. Photo by Teresa Prendusi.

Curlyleaf gumweed visited by a moth. Curlyleaf gumweed is a great source of food and nectar for pollinators in the late summer and early Fall. Photo by Teresa Prendusi.

Curlycup Gumweed (Grindelia squarrosa)

By Teresa Prendusi

The grindelias, members of the sunflower family (Asteraceae), are most commonly known for their copious amount of gummy resin (exudates) found on their flower heads. Several subspecies are found west of the Mississippi river. The common curlycup gumweed, Grindelia squarrosa, is often found along roadsides and grasslands in late June to September throughout the interior west, often following disturbances created by humans. It may be an annual, biennial or perennial plant and is readily recognized by the recurved (squarrose) bracts on the involucres (cups) that enclose the flower heads. The flowers are yellow and about an inch wide. Curlycup gumweed plants are about a foot tall with sessile leaves that are slightly serrate which often turn at right angle to the sun. This is why some species are often referred to as compass plant.

The grindelias have been used for many medicinal purposes by Native Americans, including as a wash for poison oak rashes and burns and for pulmonary troubles. The resinous sap that covers the leaves has been used as a substitute for chewing gum. Green and yellow dyes can be obtained from the yellow flowering heads and pods. Grindelias are still used for asthma and bronchitis, and in common cough remedies in homeopathic medicine. Because this plant is unpalatable to livestock and can readily absorb selenium from the soil it is considered undesirable by many ranchers.

The genus Grendelia was named in honor of the European botanist, D.H. Grindel, who lived from 1776 to 1836 in Latvia and Estonia.

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