Red valerian: characteristics, care & varieties

White- or red-flowered red valerian is excellent for combining with other perennials in sunny open spaces — the plant is perfect for stony soils.

There are several species of Centranthus, but it is mainly red valerian (Valeriana rubra; syn.: Centranthus ruber) that is often used as an ornamental plant, which is why we will only discuss this species and its varieties in this article. Below you will learn all about the properties and requirements of this pretty perennial.

Red valerian: Origin and characteristics

The species Valeriana rubra is assigned to the honeysuckle family (Caprifoliaceae). It is native to some countries in Europe, such as Italy, Portugal, Spain, France and Greece, but also to Morocco, Algeria and Tunisia. The perennial plant is found in moderately dry to fresh and lime-rich habitats, often in walls or rock crevices in which the gaps are filled with some organic material. In our country, the sufficiently hardy red valerian can be described as a deciduous perennial, although the foliage near the ground may survive very mild winters.

It tends to grow in clumps and reaches a height of 30 to 80cm. Its herbaceous shoots, which become slightly woody at the base, and the foliage are covered with a blue-green frosting. Its ovate to lanceolate, entire-edged and slightly fleshy leaves are opposite on the stems — stalkless at the top and stalked at the base.

The flowering time of red valerian extends from May to August or September. At this time the small pink or, depending on the variety, white flowers form in dense, rounded umbels. Because of the special shape of red valerians with their long corolla tube and the spur, the flower is only interesting for insects that can reach the nectar with the help of a longer proboscis. This is why some bumblebee species and butterflies are frequent visitors to this plant, despite the fact that red valerian has only a low pollen supply and a moderate supply of nectar. Later, winged fruits develop and are spread by the wind.

The most beautiful varieties at a glance

The number of red valerian varieties is quite limited and differ mainly in flower colour and growth height.

• Valeriana rubra ˈAlbusˈ: this white-flowered red valerian only grows about 40 – 60cm high.
• Valeriana rubra ˈCoccineusˈ: this red-flowered red valerian is a classic, as the variety was already rated as very good in 1979. It also only grows up to 60cm high. The flowers are a bold shade of crimson red.
• Valeriana rubra ˈRosenrotˈ: red valerian ˈRosenrotˈ forms intense pink flowers and also reaches a growing height of about 60cm.
• Valeriana rubra ˈAlbiflorusˈ: this variety is another white-flowered cultivar of red valerian that grows between 50 – 70cm tall.

Tip: the white varieties in particular are beautiful when planted together with yellow roses (Rosa). In general, especially the more undemanding wild roses work well alongside red valerian.

Planting red valerian

A moderately dry to fresh, calcareous and well-drained soil with a moderate nutrient content in sunny, warm locations is recommended for red valerian. This plant, which belongs to the honeysuckle family, is very heat tolerant and can survive dry summer periods once it has become well established. Since Valeriana rubra likes to stand on rocky substrates or gravel and shingle surfaces, it also thrives easily in stony areas or on walls if there is sufficient moisture. These should be at least damp as a result of sufficient rainfall or additional irrigation.

Planting is best done in spring. To prepare the soil, it must be cleared of weeds and loosened. Now a planting hole slightly larger than the root ball can be dug. For soil improvement in the case of dense, heavy soils, sand or gravel should always be incorporated into the hole at a volume ratio of 30%. Red valerian should now be planted just as deep as it was in the pot and then watered well. The best effect is achieved with a single plant or by using a maximum of three plants together, taking care to ensure a planting distance of about 45 to 50cm so that the plants have enough space to grow well.

The right care

The undemanding red valerian does not demand much care as long as it is in a suitable location. Additional watering is really only necessary until it becomes established and in prolonged dry spells.

There are two possible times of year for cutting red valerian. If the perennial is cut back by about a third after the first flowering, there is a chance of a repeat flowering in September. In spring, red valerian can finally be cut back close to the ground before new shoots appear.

Since the perennial has only moderate nutrient needs, fertilisation in spring is totally sufficient. The best fertiliser for this is a slow-release granulate, which releases its nutrients gently over several months and can also be applied well to stony or gravelly substrates. An example of such a fertiliser is our potassium-enriched Plantura Flower Food, which ensures stronger leaves, abundant flowering and an overall resistant, frost-hardy plant. The effect of our slow-release fertiliser extends over three months, which is why a single application is completely sufficient.

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Is red valerian hardy?

Red valerian is hardy down to temperatures of about -23 °C. In a suitable location, it will therefore survive the winter without any problems and without further protective measures. In any case, sunny, warm and wind-protected locations, such as along walls or house walls, are recommended. Only young plants can still benefit from protection with leaves or brushwood in the first few years.

Propagation

The easiest and most reliable way to propagate red valerian is by sowing seeds. In most cases, you hardly have to do anything to propagate it, as Valeriana rubra willingly self-propagates and the seedlings or young plants can later simply be transplanted to the desired location. Alternatively, the seeds are sown in advance in the intended place on the soil and pressed in. If white and red flowering varieties are present in the garden, the emergence of new colour mixtures is to be expected when sowing. If you want to prevent red valerian from spreading, simply cut off the wilted flowers and you might even get an extended flowering period.

Is red valerian poisonous?

There are basically no known toxic effects of red valerian, but its root contains special iridoids, which are also present in baldrian (Valeriana officinalis) in smaller quantities. The active ingredients of the root are used in folk medicine and are said to have a calming effect, for example when one is restless, irritable or frightened. In experiments, however, a cell-damaging and mutagenic effect of these so-called valepotriates is said to have been discovered. but the risk of plant parts being eaten by humans or animals is quite low anyway, as the iridoids protect the ornamental plant from predators with a very bitter taste.

Did you know? Red valerian is an ideal plant for black box gardening because of its self-seeding properties.