Curly-cup Gumweed
Historical Plants of the Eloise Butler Wildflower Garden
The oldest public wildflower garden in the United States






Curlycup Gumweed
Grindelia squarrosa (Pursh) Dunal
Aster (Asteraceae)
Historical - not extant
Late Summer
Other names and notes

(Gum-plant, Gum-weed, Broad-leaved Gum-plant). Curlycup Gumweed is an erect biennial or short-lived perennial growing to 40" high on smooth stems that branch at the top. It is an introduced, naturalized plant to our area. The first year the plant forms a rosette with the stem forming the second year, but some plants may flower the first year. Stems are smooth, angled and sometimes reddish. The leaves are alternate but of various shapes. They can be oblong, linear, lanceolate to ovate, from 2 to 5x longer than wide and are dotted with resinous glands. Surfaces are without hair, leaf margins are usually coarsely toothed but may be entire. Middle stem and upper leaves clasp the stem. The inflorescence is composed of branched almost flat-topped clusters of flower heads at the top of stems. Individual flower heads are 1 to over 2" wide with 25 to 40 yellow 1/2" to 3/4" ray flowers surrounding a central disk of yellow disk florets. Beneath the flower head there are 5 to 6 series of phyllaries (Bracts) that are reflexed to spreading with tips looped or hooked. These are linear to lanceolate in shape, scaly, and usually very resinous. The young flowers and buds are covered with a thick milky exuded substance which has a balsamic smell and a bitter taste. Seed: Fertile flowers produce a brown dry achene with no fluffy pappus but with 2 to 3 awns.

Habitat: Curlycup Gumweed is found in disturbed areas, plains, along streams and frequently today along roadsides. It accepts all types of soils, moderate moisture to dry, and full sun. It is tap-rooted, growing from a short vertical rhizome with extensive deep roots. Names: The genus, Grindelia, is name for David Grindel (1776-1836), a pharmacologist and doctor, who is considered the first natural scientist. The species, squarrosa, which means 'spreading' or 'recurved' is applied to plants where the bracts are spreading to recurved. Comparisons. This species is similar to G. hirsutula, the Hairy Gumweed where the stems are hairy, the leaves have few if any glands and the flower heads are not resinous.

Curly-cup Gumweed buds Curly-cup Gumweed plant
Above: Buds are covered with a thick milk exude with a balsamic odor. Below: 25 to 40 yellow ray flowers surround the central disk florets.
Curly-cup Gumweed flower
Below: Phyllaries are in 5 or 6 series with spreading hooked or looped tips, all very resinous. Below: Seeds are a dry achene with 2 to 3 awns but no fully pappus.
Curly-cup gumweed flower bracts Curly-cup Gumweed seed head
Below: The plant has many clusters of flower heads at the tops of stems. Below: Leaves are of various shapes, usually linear with toothed edges, one main vein, resinous glands and stem leaves clasp the smooth angled stem.
Curly-cup Gumweed plant Curly-cup Gumweed leaf Curly-cup gumweed stem

Notes: Curlycup Gumweed was present in Glenwood Park, which surrounded the Garden, but was not present in the Garden. So Eloise Butler transplanted some from Glenwood Park to the Garden on June 15, 1910 and again on Sept. 25, 1913 she brought in plants from 4748 Chicago Ave., Minneapolis (this is the address where, at this time period, she roomed with a friend). One additional plant was added on June 25, 1914. It was still present in the Garden at the time of Martha Crone's 1951 Garden Census, but was gone by the time of the 1986 census. Curlycup Gumweed is found throughout North America except the very far north, the Canadian Maritime Provinces and the states of the SW U.S. gulf coast. It is thought to be native to the Great Plains and Rocky Mountain area and then spread to the rest where it has naturalized. Within Minnesota it is found in about half of the counties widely scattered throughout the state as might be expected of a plant that naturalized. This includes most of the metro counties. The only other Grindelia recognized in the state is G. hirsutula, but that is less frequently found.

Uses: Curly-cup Gumweed is unpalatable to browsing mammals due to the presence of tannins, oils, resins and alkaloids. However for human medicinal use, the plant has been found useful in the first part of the 20th century. Moore states that the parts used included the buds and flowering heads when first in bloom and the leaves before flowering (Ref. #30). The dried leaves will make a tea for bronchitis or as an expectorant. The tea is aromatic but bitter. Dried flowers are used for a tincture to treat bladder infections. The gummy buds and flowers can be chewed as chewing gum. Hutchins reports that Native Americans in the Rocky Mountain area used extracts of the plant as an antidote for poison oak and poison ivy (Ref.#12). The plant is no longer listed in U.S. Pharmacopoeia.


References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applies. Distribution principally from Wi, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.  
©2013 Friends of the Wild Flower Garden, Inc. All photos and text are by G. D. Bebeau unless otherwise credited. "" 111513