The issue: Rush skeletonweed

Rush skeletonweed (Chondrilla juncea) is a taprooted, simple perennial that can grow to four feet tall. It is very difficult to control once it gets established.

In the first year, rush skeletonweed forms a rosette that looks much like a dandelion. The stems, usually one per rosette, are green, mostly leafless, and have many branches with flower clusters

Rush skeletonweed thrive in our high desert area and most often is found in sagebrush and scablands.

Rush skeletonweed reproduces by seed and lateral roots. Seeds have a pappus (tuft of hair) and are distributed by the wind. It may grow from root fragments that are four feet deep. Most germination occurs early spring, but there is also some summer germination. Average seed production is 15,000 seeds per plant.

Integrated pest management options:

· Prevention: Feed weed-free hay; keep ditch banks free of seed-producing plants; clean equipment; use weed-free seeds.

· Mechanical: Repeated mowing before flowering; repeated removal of top growth at least every 21 days to reduce root reserves; bag and discard any flowering parts.

· Cultural: Manage land to improve competitiveness of beneficial plants; don’t overgraze pastures and rangeland

· Biological: Sheep and goats will graze, but not when plants have seeds; approved gall midge, gall mite, root moth and rust help.

· Chemical: Apply herbicides to rosette in spring or fall. Be sure the target weed and crop or landscape situations are listed on the product label. Always read and follow herbicide label directions.

Combine them:

Rush skeletonweed seeds only remain viable for up to 18 months in field conditions, but once populations are established most reproduction occurs from the roots which are difficult to kill—a long-term program is essential. Combine different IPM options over a period of years to help improve the effectiveness of your efforts.

For more information, contact Ron Patterson, University of Idaho Extension horticulture/agriculture educator in Bonneville County, at 208-529-1390 or rpatterson@uidaho.edu.