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Boundary Invasive Species Society
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Biennial to short-lived perennial herb, growing up to 1 meter
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Native to most parts of North America
Curlycup gumweed
(Grindelia squarrosa)
Quick Identification
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Bright yellow flowers
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Hooked bracts
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Sticky latex on flower buds, flowers, leaves and stems
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Smooth, narrow leaves with serrated edges
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Branching stems
Impact
Impact is unknown at this time, but some believe this species may reduce biodiversity by competing with other plants. This species also accumulates selenium, posing a toxicity risk to livestock.
Management
Avoid over grazing to prevent the establishment of this species.
Flower
Bright yellow flowers with a tightly packed centre. Flower heads are covered in a sticky sap.
Leaves & Stems
Many smooth stems grow from a deep tap root. Thick, green leaves are narrow ellipse or lens shaped, usually 1-4 cm long, and are gummy to the touch. Leaf margins are closely toothed.
Roots
A deep taproot system, occasionally accompanied by a short, upright rhizome, extends far into the soil—reaching depths of up to two meters.
Reproduction & Dispersal
By seeds. Most seeds fall near the parent plant, but seeds also travel though infested gravel, water, animals, heavy machinery and vehicles.
Seeds
Typically small, brown, and achene-shaped, which means that they resemble a sunflower seed. They are dry and without hairs, but have 2 to 8 awns at the tip.
Preferred Habitat
Often found in dry, open areas, disturbed roadsides, as well as along streams.
Interesting Facts
The resinous sap that covers the leaves has been used as chewing gum.
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