Melilotus officinalis

Yellow sweetclover is a biennial or winter annual legume native to Europe, North Africa and Central Asia. It has been widely introduced as an agricultural plant and has subsequently naturalized throughout the temperate areas of the world. It is a member of the bean family (Fabaceae). The species epithet, officinalis, means “of the shops” and denotes a useful plant.

Yellow sweetclover is highly tolerant of various soil types but prefers well-drained, fertile, and non-acidic conditions. It shows exceptional adaptation to calcareous (lime-rich) and alkaline soils. Once established, it exhibits notable drought tolerance thanks to its deep taproot system. For optimal yield and vigor, however, it requires moderate, consistent moisture, particularly during its establishment phase. It is a sun-loving plant, demanding full sun exposure for flowering and seed production; shade significantly reduces its growth. As a legume, it forms a symbiotic relationship with specific Rhizobium bacteria, requiring proper seed inoculation before planting in fields where clovers haven't been grown recently. 

Its capacity for nitrogen fixation makes yellow sweetclover an invaluable green manure or cover crop that improves soil fertility. Its strong, deep taproot system physically penetrates and aerates compacted subsoils, significantly improving soil structure, water infiltration, and breaking up dense soil layers. This action enhances the productivity of subsequent crops. Furthermore, yellow sweetclover is an excellent source of high-quality forage and hay for livestock. Ecologically, its abundant, yellow flowers are a major source of nectar and pollen, making it a highly prized honey plant for beekeepers. 

Establish yellow sweetclover permanently in a meadow or grow it as a temporary winter cover crop in any garden.