Melilotus altissimus aka Tall Melilot

Melilotus altissimus, or tall melilot, belongs to the pea family, Fabaceae. Its native range lies in Europe, including Britain and Ireland. Records extend from Scandinavia south to Spain, Italy and Greece. It grows in temperate regions and may live as a biennial or perennial. The RHS also lists the Welsh name meillionen y ceirw. Its listed synonyms include Trigonella altissima, Melilotus macrorrhizus and Melilotus nebrodunensis.

This plant reaches about 4 feet [1.2 metres] in height. It flowers from June to August. Each flower has both male and female organs. Bees pollinate the flowers. Its leaves, young shoots and seedpods have recorded food uses. Plants For A Future reports that it withstands frost. The supplied sources give no hardiness zone or mature spread.

Tall melilot grows in waste ground and woods. It avoids acid soils and suits neutral to mildly alkaline ground. It accepts sandy soil, loam and clay, provided water drains well. Soil may be dry or moist. Plants For A Future lists both sun and light shade. Yet its cultivation notes say the plant dislikes shade. A sunny woodland edge therefore fits the evidence better than deep shade. These conditions offer scope for use along open woodland margins.

Bacteria form nodules on its roots and fix nitrogen from the air. The plant uses part of this nitrogen for growth. Nearby plants may also benefit from some of it. This gives tall melilot a role beyond its summer flowers. Grow it from seed sown where it will remain. Sow from spring through the middle of summer. A 12-hour soak in warm water can help seeds sprout sooner. This may help when the weather is dry. Seeds usually sprout within two weeks.

Recorded food uses include cooked leaves and seedpods in soup. Young shoots are also cooked, and the plant serves as a flavouring. These uses come with an important safety limit. Plants For A Future warns that dried leaves can be toxic. It links this risk tentatively to coumarin and impaired blood clotting. Its food guidance restricts use to fresh material. The dried plant also has a recorded use for deterring moths. The same source lists no known medicinal uses.