Ministry of Agriculture
Rush Skeletonweed (Chondrilla juncea)
Taprooted perennial reproducing primarily by seed but also by shoot buds produced on lateral roots.
- 2 to 4 feet tall:
- Lower 6 inches of stem covered with stiff, downward pointing, brown hairs. Remainder of stem hairless.
- Much branched wiry stems contain a white, milky juice.
- Bottom leaves form a rosette and look similar to dandelion. These leaves are 1/2 to 1 1/4 inch wide and 2 to 5 inches long.
- Stem leaves arising from the branch axils are small, narrow and linear (sometimes toothed). These leaves are generally inconspicous from a distance, giving the appearance of a "skeleton-like" plant.
- Yellow; 3/4 of an inch in diameter, composed of 7 to 15 individual florets.
- An average of 1500 flowerheads are produced per plant.
- Flower heads are produced individually or in groups of two to five along or at the ends of the stems.
- Flowers from early summer through until frost.
- Slender, vertical taproot penetrating to 8 feet or more with one or more rhizomatous lateral roots primarily in the upper 2 feet of soil. These lateral roots give rise to satellite plants.
- Can produce up to 15,000 seeds per year. Each seed has a parachute of fine hairs which aids wind dispersal.
|Dandelion-like basal leaves with downward pointing, stiff hairs on stem.||Severe rush skeletonweed infestation|
Concern:Rush skeletonweed was first discovered in B.C. in the North Okanagan region of Spallumcheen in 1983. Subsequent infestations were found at Sirdar in the Central Kootenay region in 1991 and Kimberley in the East Kootenay region in 1998. Native to southern Russia and now spread throughout much of the world, this weed poses a serious threat to B.C. rangelands and other agricultural resources including both dryland and irrigated cereal production.
Over 5 million acres have been infested in the Pacific Northwest states and it is currently spreading at a rate of 100,000 acres per year. Since its introduction to Australia in 1935, the expansion of rush skeletonweed has resulted in estimated annual losses to wheat production in excess of $30 million.
Damage causedRush skeletonweed's extensive, long lived root system enables it to effectively compete with crops for water and nutrients, especially nitrogen. Once established, rush skeletonweed can reduce crop yields by as much as 70 percent. The high fibre content and milky juice in the stems also greatly hamper harvest and tillage operations. Infestations on rangelands displace beneficial forage vegetation required by livestock and grazing wildlife.
Ecology:Rush skeletonweed is adapted to a wide range of climatic and environmental conditions. Infestations are known to occur in areas receiving less than 10 inches and more than 60 inches of precipitation. Rush skeletonweed grows in soils ranging from acid to alkaline, but thrives best on well-drained sandy or gravel soils. Infestations in British Columbia to date are found in gravel pits, cropland with heavy soils, rough pasture and rangeland with light soils, as well as coarse soils along transportation corridors.
What Can You Do?Preventing seed production must receive top priority to avoid further spread of rush skeletonweed to uninfested areas.
- BE AWARE. Learn to identify rush skeletonweed.
- Prevent plants from going to seed. Cut or pull isolated plants before flowering. If flowering has occurred, bag and remove plants for burning.
- Control established plants with selective herbicides.
- Do not hesitate. Control small infestations immediately.
- Clean equipment, tools, vehicles and footwear before leaving infestations.
For control information and to report sitings, contact:
Dave Ralph, Provincial Weed Technologist,
B.C. Ministry of Agriculture
Phone: 250 371-6062
Report sitings to your local Ministry of Agriculture or B.C. Ministry of Forests office.