Skeletonweed (Chondrilla juncea) may be known by many names – rush skeletonweed, devil’s grass, nakedweed, gum succory – but whatever you call it, this non-native plant is listed as invasive or a noxious weed in a number of states. This makes managing skeletonweed a primary concern.
Killing rush skeletonweed isn’t easy. It is extremely resilient and resistant to mechanical and cultural methods of control. Since it is so persistent, the question is how to control skeletonweed?
About Skeletonweed Control
Rush skeletonweed is thought to have been introduced to eastern North America via contaminated seed or animal bedding around 1872. Today, this nearly 3 foot (just under a meter) herbaceous perennial has spread across the country.
It reproduces by seed as well as lateral roots that, even when broken, determinately produce a new plant. This dogged determination to reproduce makes managing skeletonweed a challenge. Since it can re-sprout from root fragments, mechanical control by pulling, digging, or disking is ineffective unless consistent (6-10 years) mechanical controls are applied.
Also, burning is ineffective in managing skeletonweed as is livestock grazing, which seems to just disperse rootstock that results in additional plants. Mowing is inadequate skeletonweed control as well.
How to Control Skeletonweed
The only successful non-chemical method of killing rush skeletonweed is the introduction of the rust fungus (Puccinia chondrillina). First introduced in Australia, it has since been used as a bio-control in the western United States, though with less stellar results. Since this sole bio-control was not effective in killing the invasive weed, two additional bio-controls have been added to the mix: skeletonweed gall midge and skeletonweed gall mite, which appear to be reducing the incidence of the plant in states like California.
Otherwise, the only other option for killing rush skeletonweed is with chemical controls. Herbicides are often inadequate because of the extensive root system and lack of leaf area on the plant. However, for large-scale infestations, it is the only option.
Always read and follow the manufacturer’s safety and application instructions. Successful skeletonweed control will rely on several applications. The herbicides that give the best results are fall applications of picloram alone or picloram combined with 2, 4-D. Clopyralid, aminopyralid, and dicamba also affect the root system and can be of assistance in managing skeletonweed.