Ononis spinosa

Ononis spinosa is a beautiful wild plant. It is well known for its medicinal properties but is rarely used in gardens despite the ornamental value of its summer flowering. Its ability to grow in difficult soils, where few plants can thrive, is also a great asset. This spiny subshrub produces charming pea-like flowers, usually pink-violet, sometimes white or lilac. With its deep-rooted system, it offers exceptional resistance to ploughing and is also known as "stop-ox". Give it what it likes: a poor and stony slope, even clay-limestone soil, or sandy soil, and plenty of sun.

Once widespread in Europe, Asia Minor, and North Africa, Ononis spinosa is a plant of the Fabaceae family that has become rather rare, probably due to the disappearance of its natural habitat consisting of dry meadows, roadside edges, cultivated fields, as well as sandy dunes or peat areas. This plant shows a clear preference for calcareous, clayey, or sandy, poor, and dry soils. Restharrow forms a bushy tuft, a bit tousled, up to 40 to 50cm (16 to 20in) high (sometimes much more) and 50 to 60cm (20 to 24in) wide when mature. It develops from a woody stump anchored to a powerful, acrid-smelling taproot that penetrates deeply into the soil. It is this root, rich in saponins, that is used in herbal medicine. Flowering occurs from June to August. The pink, papilionaceous flowers are gathered in leafy, pendulous inflorescences. They are followed by somewhat hairy pods. The plant develops reddish stems that are partly erect and partly prostrate, showing two hairy lines and bearing thorns. The leaves are divided into 3 small, toothed, hairy leaflets, dark green in colour.

Ononis plants can sometimes be difficult to acclimatize in the garden if the preferred conditions are not met, namely: a very sunny exposure and a well-drained soil, especially in humid climates. Considered rightly as a green manure and soil fixer, it will find its place in a wild garden, a dry garden, a garrigue-like slope, or a sunny rockery. It is also useful for decorating the degraded areas that often surround newly built houses. It looks stunning alongside Callirohe involucrata, the magenta-flowered Poppy Mallow, blue or white lavenders, or Cerastostigma griffithii. It also pairs well with Amorpha canescens, Malvastrum lateritium, or Teucrium chamaedrys, which appreciate the same growing conditions.

Depending on the region, this pioneer plant is also called "donkey herb", as donkeys seem to enjoy scratching their backs on its thorns.