Johnson County Secondary Roads Wild Sunflower Weed

Wild Sunflower (Allaria petiolata)

Description: Wild sunflower, or common sunflower, is an annual, reproducing by seeds. It should not be confused with domestic sunflowers and the perennial low-growing sunflowers, which are prairie wildflowers. The wild sunflower is largely a problem in cultivated land. Wild sunflower has a fibrous root system. The stem is erect, simple to much branched, scratchy, and may reach 10 feet in height. The leaves are alternate, simple, rough, hairy, ovate or heart-shaped, with toothed edges. The heads are showy, with yellow to orange-yellow ray flowers and brown or dark reddish-brown disk flowers. The seeds are shaped like the commercial sunflower seeds bought at stores. Sunflowers begin to grow in early June, flower in August to October and mature seed in late August to October.

Distribution: Wild sunflower grows throughout Johnson County and Iowa. Sunflowers grow on almost all soils and are most frequently troublesome in cultivated fields. Wild sunflower typically grows on idle land, waste areas, cultivated fields, and roadsides.

What’s The Problem?: Wild sunflower competes very aggressively with row crops for nutrients, water, and sunlight. It also produces large amounts of seed, which regrow the following year. Crop yields and marketability may be lowered when harvested from fields with wild sunflower infestations.

Management Methods: Cultural practices can aid in preventing infestation of wild sunflower. Use of tillage, cultivation, rotary hoe, and crop rotations are primary tools to keep establishment to a minimum. Hand pulling or cutting, mowing, and careful use of broadleaf herbicides are all tools to prevent growth of wild sunflower. Be sure to read and fully understand chemical labels before usage. Be sure to properly identify this species.

Above photos couresy of Weeds of Nebraska and the Great Plains published by Nebraska Department of Agriculture

Welcome to Johnson County Secondary Wild Sunflower Weed

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