Black medic (Medicago lupulina), also known as yellow trefoil, hop medic, black nonesuch, blackweed, or black clover, was originally introduced to North America from Europe and Asia many years ago for agricultural purposes. Since that time, this fast-growing plant has naturalized and is found growing along dry, sunny roadsides, vacant lots, weedy meadows, and other waste ground across much of the United States and Canada. Although black medic is considered a common weed, it does have certain herbal uses. Read on to learn more about this interesting herb.
I. Appearance and Characteristics
Medicago lupulina, commonly known as black medick, nonesuch, or hop clover, is a plant of dry grassland belonging to the legume or clover family. Plants of the genus Medicago, or bur clovers, are closely related to the true clovers (Trifolium) and sweet clover (Melilotus).
The generic name Medicago is derived, via Latin medica, from Ancient Greek Μηδική (Mēdikḗ) “Median”, because alfalfa was believed to have been introduced from the region of Media (now in Iran) in antiquity. The specific name lupulina means “wolf-like”, and refers to the hop, or willow-wolf. Its scientific name is a translation of the common name hop clover (or hop-clover), which is also used for several members of the genus Trifolium.
Also spelled “medic” or “meddick”, the plant is known by a number of alternate names, including nonesuch, black nonesuch, black medic clover, hop clover, hop medic, black clover, black hay, blackweed, English trefoil, hop trefoil, and yellow trefoil. Some of these names are also applied to wildflowers of the related genera Trifolium and Melilotus.
Medicago lupulina is an annual or short-lived perennial plant, growing each year from adventitious buds on the roots. Mature plants measure from 15 to 80 cm (6 to 31 in) in height, with fine stems often lying flat at the beginning of growth and later erecting. The leaves are compound, each with three oval leaflets, carried on a short petiole; the center leaflet usually has a longer petiole. The leaflets are hairy, toothed toward the tip, and differ from those of the similar Trifolium dubium in that they end in a short point.
Black medick has small (2–3 mm) yellow flowers grouped in tight bunches (compact racemes). On larger plants the flower heads may reach 8 mm (5⁄16 in) or more. The fruit is a single-seeded pod, 1.5 to 3 mm in diameter, that does not open upon maturation, but hardens and turns black when ripe. Each pod contains a single amber-colored seed.
Like other legumes, the roots of black medick contain nodules hosting nitrogen-fixing bacteria. Plants that survive for more than one year may develop a deep tap root.
A native of the old world, black medick is found throughout Europe, north Africa, the Near East, and most of Asia, including India, China, and Korea. It is naturalized in central Asia, Japan, South Africa, Australia, New Zealand, the United States, Canada, and much of South America. Black medick is found throughout the United States, including Hawaii and Alaska.
Black medick thrives in dry to moist, well-drained soils containing sand, loam, or clay, and is a pioneer plant, often growing on disturbed ground. It grows in alkaline, neutral, and mildly acidic conditions. It does not grow in shady areas. Black medick grows well in limestone soils and on coastal sand dunes, where it suffers less competition from the other plants, and as such is found on many islands, such as Taiwan, the Canary Islands, the Azores, and Madeira. It is resistant to cold and can be found on mountains up to 1,800 meters.
II. How to Grow and Care
Sunlight
Black medick thrives best in full sun conditions, benefiting from long hours of direct light for robust growth and health. While it prefers this intense light environment, the plant demonstrates a degree of flexibility, tolerating partial sun as well. This adaptability means black medick can withstand some shade, though too much could result in less vigorous growth and diminished flowering potential. Black medick does not require any specific adaptations or indoor placement, as it is predominantly an outdoor plant. In gardens, black medick should be situated in spots that receive generous sunlight, which ensures optimal development.
Watering
Originating from regions with moderate climates, black medick has adapted to maintain a balance in water retention, showing resilience in various moisture conditions. It thrives best when provided with consistent moisture and benefits from watering every week. Its drought tolerance allows it to withstand periods of low water availability, making it a versatile species for different environments. Given its adaptability, black medick is commonly grown outdoors where it can benefit from natural rainfall patterns. This herbaceous plant’s growth cycle is closely tied to water availability, influencing both its vegetative and reproductive phases.
Propagation
Black medick is best propagated through sowing seeds during the ideal season of Spring. The propagation process is relatively easy, with successful germination indicated by emerging seedlings. No special tips are needed for effective propagation.
Transplanting
The ideal season for transplanting black medick is during late winter to early spring (S2-S4), promoting root growth with cool, moist conditions. Choose a sunny location to enhance its growth. It’s crucial to ensure the soil is well-draining to prevent root rot.
III. Uses and Benefits
- Medicinal uses
Black medic extract reportedly has antibacterial qualities and may be effective as a mild laxative. However, it may increase blood clotting and shouldn’t be used by people who use blood thinning medications. Black medic should also be avoided by children, the elderly, and pregnant women.
- Other uses
Black medick is a good source of nectar for bees to use to make honey. It is frequently found in natural pastures, and may be planted in order to create artificial meadows, especially on dry land. The presence of black medick in large concentrations as a lawn weed may indicate that the soil is poor in nitrogen. However, because black medick and other clovers fix nitrogen in the soil, this deficiency can improve over time due to the presence of these plants.
Black medick is sometimes used as a fodder plant. Its hardiness and ability to grow in poor soils, as well as its tendency to fix nitrogen in the soil, make black medick a good choice for pasturage, although its fodder value is limited. It is grazed by sheep but is not very palatable to cattle.