The issue: Bur buttercup

Bur buttercup (Ceratocephala testiculatus) is a winter annual that germinates in late-fall and early-spring when soil temperatures are cool. This non-native, low-growing weed does not have vegetative stems; only a low mound of antler-looking leaves.

The small, yellow, five-petaled flower is borne on a short stalk; and the resulting oval, bur fruit is similar, in size and shape, to a cocklebur.

Bur buttercup is highly toxic to livestock, but this is only an issue in poorly managed pastures where there is little other feed available. It is commonly found in dry areas where cheatgrass thrives, roadways, rights-of-way, lawns, flower beds, vegetable gardens, orchards, ditch banks, and poorly managed pastures.

Integrated pest management options:

· Prevention: Eliminate seed-producing plants; keep ditch banks free of seed-producing plants.

· Mechanical: Shallow tillage; hand-pull bur buttercup from flower, shrub, and vegetable beds. Burn with weed burner in early spring.

· Cultural: Manage landscapes, gardens and pastures for competition of desirable plants—deep and infrequent irrigation; fertilize properly; aerate compacted soil; raise mower height above three inches; landscape fabric mulch or a three-inch organic mulch in flower beds.

· Biological: None.

· Chemical: Late-fall and early-spring pre-emergent herbicides—minimize soil disturbance after pre-emergent is applied. Effective post-emergent herbicides include 2,4-D, chlorsulfuron, dicamba, glyphosate, metsulfuron, triclopyr; some are not appropriate for home landscape use. Be cautious when applying herbicides in areas where tree and shrub roots grow. 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: Bur buttercup seeds can remain viable for several years—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.