Those botanists. Always changing the rules. Sweet clover, so-called for its
sweet, haylike scent, used to come in several varieties, notably white (Melilotus alba) and yellow (M. officinalis). Now they are considered one and the same, at least according to the USDA Plants Database, which
we use as the standard for herbaceous plant names. It isn’t the botanists’ fault though. Naming
plants in a way that reflects their relationships to each other is a complex and subtle business.
Sweet clovers are European and Asian natives, introduced and now widespread in North America.
Identification: Plants are 24-84" (60-213 cm) tall, often branched,
bushy or gangly in appearance. Stems are fairly straight but not necessarily erect; sometimes they
sprawl along the ground or over other plants. They are hairless. Leaves are alternate, occurring in clover-like clusters of
three. Leaflets are ¾" (1.9 cm) × ¼" (6.3 mm), oval, with slightly toothed edges. Long, curving spikes contain tiny, pea-like
flowers that are yellow or white. Each flower is ⅛-³/₁₆" (4-6 mm) long. The flower spikes are probably the most obvious identifying feature. Flowering occurs from June to September. Fruits are oval-shaped, ¹/₁₆-⅛" (3-4 mm) long, with raised veins.
Edibility: Fresh young leaves, shoots, and seedpods can be eaten raw. However,
sweet clovers contain coumarin. While coumarin is responsible for their appealing smell, if the plants develop
mold, coumarin is converted to dicoumarol, a blood thinner that is poisonous in significant amounts.
Moldy or dried leaves may be toxic !
(If you know someone taking Coumadin, a drug used in carefully controlled amounts to prevent clotting
of the blood, it is derived from dicoumarol.)
Medical: Sweet clover has been used to treat a wide range of
ailments, and there is some evidence that at least some of these treatments, such as for varicose veins,
convey real benefits. However, given the blood-thinning effects of improperly harvested or prepared
plants, we don’t recommend its use. See this Plants for a Future article,
or this one on medicinenet.com, for further information.