Melilotus officinalis

Native to Asia, Europe, and the Indian subcontinent. Introduced and naturalized in North America.

Dry. Open, upland areas, prairies, disturbed sites, roadsides. Full sun or partial shade, never full shade.

Late May to September

Yellow

1′ to 6′

This is a 1′ to 6′ tall, erect, freely branching, biennial forb rising on many stems from a strong taproot. The stems are branching, light green, and hairless. The taller plants tend to be bushy, the shorter plants lanky. In the first year they are small and do not flower. In the second year they are taller, bushy, and produce many flower clusters.

The compound leaves are alternate, hairless and divided into three leaflets.The leaflets are oblanceolate or obovate, ½″ to 1″ long and up to ¼″ wide. They are plain green, finely toothed along the middle and upper margins, the teeth pointed outward rather than forward. The middle leaflet is on a distinct stalk.

The inflorescence is many tall, spike-like clusters of stalked flowers. The clusters are on elongated stems produced in the axils of the middle and upper leaves. The flowering stems are 2″ to 6″ long. Dozens of small flowers are crowded along the top two thirds of the stem.

The flowers are ⅛″ to ⅓″ long and are attached to the stem with a minute stalk. They droop down but ascend at the tip.

White sweet clover (Melilotus albus) has white flowers. It is usually a little taller than yellow sweet clover. The foliage is grayish-green, not plain green. It blooms 2 to 3 weeks later than yellow sweet clover.