Rush Skeleton Weed (Chondrilla Juncea)

Class B Noxious Weed in Benton County

A single plant can become an entire colony. Without control measures, this weed will produce a mono-culture of interconnected plants. In addition to its deep regenerative root system, Rush Skeleton Weed has prolific seed production and far-reaching dispersal capabilities because the seeds ride on the wind.

 Rush Skeleton Rosettes

Rush Skeleton Rosettes

 Rush Skeleton Growing Stems from Rosettes

Rush Skeleton Growing Stems from Rosettes

Identify:

Rush Skeleton Weed forms a rosette that looks like dandelion. The leaves of the rosette are hairy on both sides and have lobes that point backward toward the base of the plant.

A stem that has coarse, brown, downward pointing hairs grows out of the rosette. The upper part of the stem is smooth. This stem becomes highly branched with few leaves.

Flowers are yellow, no more than ½inch, and can appear singly or in clusters of two to five.

Thick white latex exudes from the leaves, stems and roots when broken or cut.

 Stems Highly Branched, No Flowers Yet

Stems Highly Branched, No Flowers Yet

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 Flowers bloom in July. Seed production peaks in July and August but can continue into November.

Flowers bloom in July. Seed production peaks in July and August but can continue into November.

 

 Flowering stems usually die in October when a new rosette appears. The dried skeletons of old plants are still visible. 

Flowering stems usually die in October when a new rosette appears. The dried skeletons of old plants are still visible. 

Control Methods:

The best control strategy is prevention. Learn to identify the plants as rosettes and continually eliminate them as soon as they appear.

Don’t till or cultivate patches of Rush Skeleton because the roots easily break into fragments that will develop into new plants. This makes the infestation worse. Mowing is not effective.

You can get control of a very small infestation by diligent hand pulling two or three times a year, for six to 10 years. If you apply herbicides twice a season at the right times you can get a handle on an infestation in 3 years. This aggressive re-application program includes spraying in the spring when the plant is still a rosette, no later than when it is about to bolt and spraying the new rosette later in the fall. This is a perennial weed and if you spray only once, use an herbicide with a residual in the fall. Use an adequate, labeled rate to kill the weed, but allow it to live long enough to translocate the herbicide. Also use a MSO surfactant with your spray because of the waxy leaf surface.