Skeletonweed almost as scary as it sounds
If the name “skeletonweed” isn’t ominous sounding enough, then the fact that this invasive plant has a taproot that can reach depths of 2.5 metres and occupies over five million acres in the western U.S. should send shivers down your spine.
Rush skeletonweed, also known as gum succory, devil’sgrass, naked weed or hog-bite, is a perennial whose branched stems can reach heights of up to 1.3 metres and appear leafless or “skeleton-like.”
Plants begin as a basal rosette of leaves that look similar to a dandelion, and then grow one to six branching flowering stems. Plants exude a latex sap from injured surfaces.
Small yellow flowers begin in early summer and continue until frost in the fall. Seeds mature nine to 15 days after the flowers open.
Each seed has a parachute of fine hairs which allow it to travel long distances by wind, but seeds are also dispersed by water, animals and humans. While rush skeletonweed spreads primarily by seed, it also spreads by shoot buds found along lateral roots and near the top of the main root. It additionally grows from root fragments in the soil.
Fortunately we have very little of this invader growing in the Okanagan-Similkameen. In fact, prior to last week we only knew of one outbreak along Highway 97 just outside of Okanagan Falls.
Unfortunately, we have now discovered a second outbreak along Green Lake Road near the shale slide. We’ve worked co-operatively with the Ministry of Transportation to take immediate action, but there remains a concern that rush skeletonweed may be more widely occurring than we think.
Rush skeletonweed’s native range extends from western Europe and northern Africa to central Asia. It was accidentally brought to the U.S. as a contaminant of fodder in 1914, and has since become widespread in wheat-growing regions and rangelands of Idaho, Oregon and Washington.
Skeletonweed is listed as provincially noxious under the B.C. Weed Control Act, and is classified as noxious, prohibited or banned throughout the western U.S. states.
In B.C., rush skeletonweed was first identified in the North Okanagan region of Spallumcheen in 1983. Subsequent infestations have been found in Crescent Valley, Kimberley, Windermere and Creston, and as mentioned, near Okanagan Falls.
Rush skeletonweed is adapted to a wide range of conditions, particularly dry grasslands with well-drained, light-textured soils. It readily invades rangelands, cropland, roadsides and other disturbed habitats such as gravel pits. Its extensive, long-lived root system enables plants to effectively compete with crops; however, dense monocultures will typically not form in healthy native plant communities.
Plants are particularly troublesome in croplands, where the plant’s milky latex can hamper harvest and tillage operations.
This aggressive invader poses a serious threat to B.C. rangelands and other agricultural resources. Because we have such limited distribution of rush skeletonweed in the South Okanagan, it is one of our highest priority invaders for treatment and our goal is eradication.
Any possible sightings of this plant should be reported immediately. Early detection and immediate action are the key to success.