Broadwater County Noxious Weed District Article
Author: Jessica Bushnell, Broadwater County Weed and Mosquito Control
Broadwater County Noxious Weed District Article
Jessica Bushnell
Broadwater County Weed and Mosquito Control
Broadwater County Noxious Weed District has identified two new populations of Rush Skeletonweed and a single population of Ventenata. Both of these populations were identified along the I-90 section of Broadwater County, and we found a single plant of Rush Skeletonweed by the Bleu Horses. Both sites have been surveyed, treated, and plans for future monitoring have been made.
But what are Rush Skeletonweed (RSW) and Ventenata? Both plants are on Montana’s Noxious Weed List. Rush Skeletonweed is a PRIORITY 1 B. These weeds have a limited presence in Montana, and management criteria require eradication, containment, and education. Ventenata is a PRIORITY 2 A. These weeds are common in isolated areas of Montana. Management criteria will require eradication or containment where less abundant.
This week, we will cover Rush Skeletonweed.
Rush skeletonweed is a perennial (plants that live for more than two years) with many branched, wiry, and stiff stems that grow from 1 to 4 feet tall. The lower part of the stem is covered with stiff, golden-red, downward-pointing hairs. The plant exudes a milky liquid when it is damaged.
The stem leaves are alternate, meaning they grow staggered along the stem rather than directly opposite each other, and they are narrow. They can grow up to 4 inches long. As the plant produces flowers, these leaves will die off, leaving the plant with a bare, skeletal appearance. The lower leaves resemble a common dandelion and are hairless, featuring deep, irregular teeth that point back toward the leaf base. These lower leaves can grow up to 5 inches long.
Rush skeletonweed has small yellow flowers and feathery seeds that ride the wind. The flower heads are half an inch across and will produce seeds without fertilization. Flowering usually occurs in late summer. The seeds are small, brown, tapered at both ends, and have fluffy white tufts that grow outward from the seed connections. First-year plants can produce 50 to 150 flower heads annually, equating to 500 to 1,500 seeds per plant. Older plants can produce 20,000 seeds annually.
It thrives in well-drained sandy or gravelly soils and has also spread across large areas of shallow silt loam soils. In addition to deep (8+ feet) taproots, it has rhizomes (root systems that spread outward and can grow new stems) that produce daughter rosettes. Plants also grow from buds on root fragments cut by cultivation or other equipment.
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PhotoCredit: Jessica Bushnell
Image 1 Caption: Rush Skeletonweed
Photo Provided by Jessica Bushnell
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