Centranthus ruber

Centranthus ruber, or red valerian, is a robust perennial that forms a beautiful rounded and floriferous clump. Its generous flowering extends from May-June until August, gathering a multitude of butterflies around its almost red inflorescences that resemble small clusters of lilac from a distance. Almost fail-proof, comfortable in almost any climate, endowed with the indefinable charm and untamed character of wild plants, it brings lightness to flower beds and shrubs.

Originally from southern Europe, North Africa, and Asia Minor, red valerian has recently been classified in the Caprifoliaceae family instead of the Valerianaceae family. Indeed, unlike the flowers of usual valerians, its tiny flowers are equipped with a long arched spur, which serves as a nectar reservoir for butterflies. It is a powerful herbaceous perennial plant with a woody rootstock anchored in rhizomes. It grows in an erect to spreading bushy clump, reaching an average height of 60cm (24in) with a diameter of 50cm (20in), depending on growing conditions (it is often taller in fertile soil). The clump is composed of hollow and fleshy, brittle stems covered with bloom. They bear small deciduous to semi-evergreen leaves depending on the climate. The thick and fleshy leaves are jade green to glaucous green or grey-green. They wrap around the upper part of the plant. They are petiolate towards the base of the clump, and ovate to lanceolate in shape. Their dimensions do not exceed 2 to 4cm (1 to 2in) in length and 1.2cm (1in) in width. Flowering occurs from May to September, sometimes almost all year round in very mild climates. The tiny carmine pink flowers, grouped in ramified corymbs, are carried on the upper part of the stems above the foliage. They are highly nectar-rich. Note that this perennial plant will live longer in dry and poor soil. It self-sows spontaneously in light soils.

Red valerian, like gauras, Erigeron karvinskianus, and even herbaceous peonies, is one of those almost fail-proof perennials that deserve to be included in every garden. Very floriferous and not demanding on the nature of the soil as long as it is well-drained, centranthus plants grow freely in a garden, filling in the empty spaces between perennials or shrubs. They even grow spontaneously in wall crevices. They bring lightness to flower beds and are very useful for quickly filling a poor embankment or a new garden. They are excellent plants for dry gardens, often lacking flowers in summer. Varieties with white, pink, mauve, or red flowers can be planted with each other to create beautiful colourful displays. They can also be combined with dry-land euphorbias, centaureas, poppies, damask nigellas, and many others.