Goatsrue

Domestic Programs Pest Evaluation. Arthur E. Miller, USDA-APHIS-PPQ, AERO, Raleigh, NC. November 16, 2001

Scientific name: Galega officinalis (Fabaceae)

Physical description: Goatsrue is a seed-propagated perennial. Each plant tends to form a crown and ranges 2-6 feet tall. A plant may have 20 stems and a deep taproot. The first seedling leaves are large, oval, and dark green. Mature leaves are alternate, odd-pinnate with six to ten pairs of leaflets. Each leaflet has a small hair-like projection on its tip. The stems are hollow cylindrical, and tubular. The stipule (leaf-like appendage at the base of the leaf stem) is sagittate (arrow shaped) and toothed and lobed.

The white and bluish to purplish pea-like blossoms are borne in terminal or axially racemes. Flowering begins in June and continues until frost in the fall. Each blossom produces a straight, narrow, smooth pod, which points outward and is angled slightly upward from the stem. There are 1-9 seeds per pod and there may be upwards of 15,000 pods per plant. Goatsrue seeds are bean-shaped, dull yellow in color, and about 2 ½ times larger that alfalfa seeds. Goatsrue seed typically remain dormant until scarified and may remain viable for ten years.

Origin and North American Distribution: Goatsrue was introduced from the Middle East to Utah in 1891 as a livestock forage, but it is unpalatable and lethal to sheep. It has been found recently in PA, NY, & WA.

Quarantines: It is a Federal Noxious Weed with a very limited distribution nationwide. It is a State Noxious Weed for PA & NV.

Dispersal: Seeds drop to the ground when mature and may be spread by water, equipment, or animal manures.

Control: Property managers and cooperators may use these strategies:

Cultural Control. Mowing, clipping, cutting, and shallow cultivation are poor means of control because the plant will flower and produce seed even when very small. Alternate cropping and row crops are effective deterrents since the cultivation interrupts the life cycle of goatsrue. It helps to induce germination of seed in the soil and treat the seedlings chemically to eradicate them.

Chemical Control. Use of selective herbicides are the major control method and the rates used in Utah are typically 1 lb. a..i. 2,4-D/acre and 0.5 lb. A.i. Dicamba/acre. Crowns of treated plants may remain viable up to seven years unless retreated or excavated and removed.

Biological Control. None are known.

Economic impact: Goatsrue is toxic to ruminants. The alkaloid content is highest in the spring. Animals will avoid the goatsrue, which contributes to the establishment and spread in rangeland. It is found in established alfalfa fields. The plant is considered an ornamental species and a medical herb. Eradication efforts are costly and time consuming.

Environmental impact: Goatsrue is capable of forming a monoculture in wetland communities, displacing native or beneficial plants.

Benefits of control: Eradication of goatsrue can restore pastures and other land to productivity.