Hippocrepis emerus aka Scorpion Senna

Hippocrepis emerus, or scorpion senna, belongs to the pea family, Fabaceae. Its older name is Coronilla emerus. Its native range spans Europe, the Mediterranean region and the Caucasus. It grows in temperate regions and is not native to Britain or Ireland. Wild plants occur in open woodland and rocky limestone hills. In gardens, it suits the sunny edge of woodland.

This deciduous shrub forms a rounded bush with leafy growth. Garden plants reach about 5–8 feet (1.5–2.5 m) tall and wide. The RHS description gives around 6.6 feet (2 m) as a usual height. Plants take five to ten years to reach full size. The bright green leaves are pinnate, with small leaflets. Their divided shape gives the shrub a light, fine texture. The leaves fall before winter, leaving the branch framework bare.

Pale yellow flowers grow in small clusters from late spring into autumn. This long flowering season gives the shrub value in mixed borders. Thin green seed pods follow the blooms. Each pod can reach about 0.33 feet (0.1 m) long. The pods add another feature after the flowers fade. Plants For A Future also lists the species for scent and nitrogen fixation.

Choose full sun and shelter from cold winds. A south-facing or west-facing site suits its needs. Grow it in light soil with moderate fertility and good drainage. Chalk, loam and sand are all listed as suitable. It accepts acid, neutral and alkaline soils. The RHS rates it H5 for UK hardiness. Plants For A Future lists USDA zones 5–9. Suggested settings include coastal plots, courtyards and cottage gardens. It also fits flower beds and borders beside walls.

The RHS reports few usual pest or disease problems. Raise new plants from seed or semi-hardwood cuttings. Cut sparse, leggy plants back near ground level in spring. This can renew their growth and improve their shape. Plants For A Future records no known edible uses. It gives the plant a low medicinal rating, citing cardiac and diuretic uses. These records do not establish that home use is safe. That source found no species-specific report of poisoning, but still advises caution. Its warning rests on poisonous relatives, not confirmed toxicity in this species.