Download Curly cup gumweeds

THE ENEMY: Curly cup gumweed (Grindelia squarrosa)
Strategy: This is a light-green biennial or short lived perennial with bright yellow flowers and
belongs to the aster family (thistles and knapweeds). It gets it name from the outer coating of
its seed head that has curly bracts that are sticky or gummy. At maturity the plant will reach a
height of two feet and is prevalent in pastures as well as roadsides. This native plant has leaves
that appear to be succulent or ‘fat’.
Attack: This plant has no forage value to livestock or wildlife, therefore it can continue to
spread each year unless controlled or at least managed. Once established the plant does an
excellent job competing against desirables for food and water. This is very bad as the plant is
very drought tolerant which allows it to invade much more effectively especially along roadways.
The dead winter plants have a distinguished round seed-head with leafless stems.
DEFENSE: Because this is not a noxious weed there is a limited amount of biological control
research is available.
Due to its thick gummy coating over the entire plant herbicide control is
very difficult. Therefore you must think of ways to promote better herbicide absorption into the
plant. This can be done by utilization of products known as surfactants. These products not only
help spread the spray droplets across the leaves, but they also help the herbicide penetrate
through the cuticle (outer covering of leaf surface). Using these surfactants with good herbicides
such as Escort XP, Opensight, or Milestone will give you great results. If you choose to dig the
plant up make sure that you get down into the ground at least 5 inches.