With its red or white flower umbels, the red valerian brings color to the bed. The summer bloomer feels particularly good in hot, dry places.
Profile of red valerian:
Scientific name: Centranthus ruber
Plant family: honeysuckle family (Caprifoliaceae); subfamily valerian family (Valerianoideae)
Other names: spur valerian, kiss-me-quick, fox’s brush, devil’s beard, Jupiter’s beard
Sowing time: by September at the latest
Planting time: spring or late summer
Flowering period: April to October
Soil quality: stony to sandy, calcipholous, lime tolerant, nutrient-poor to moderately nutrient-rich, low in humus
These information are for temperate climate!
Use in: flower beds, flower bouquets, single position, group planting, planters, rose companions, dry stone walls, overgrowing, borders, cottage garden, flower garden, natural garden, rose garden, rock garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 6 (-20 °C / -5 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of red valerian
Plant order, origin and occurrence of red valerian
The red valerian (Centranthus ruber) is one of many valerians (Centranthus) within the honeysuckle family (Caprifoliaceae). It originates from Mediterranean Southern Europe, Northwest Africa and Asia Minor, but the hardy plant is now also common in much cooler areas. The valerian belongs to the subfamily of the valerian family (Valerianoideae), and its root supplies larger quantities of the medically effective iridoids than the well-known valerian (Valeriana officinalis).
Characteristics of red valerian
The red valerian grows upright, persistent and herbaceous, with a slight lignification at the base. It grows to a maximum height of 80 centimeters (32 in).
The blue-green leaves of the plant are opposite and have a lanceolate to ovoid shape. They have entire margins and grow up to 8 centimeters (3.2 in) long. While the base leaves grow on short stems, the upper leaves are heart-shaped at the base and sit directly on the branches.
Many small blossoms stand together between April and October in a bearing golden inflorescence. It got one of its name, spur valerian, because of the five to ten millimeter (0.2 to 0.4 in) long spurs that sit at the lower end of the flowers.
The blossoms of the red valerian turn into fruit in autumn. These are carried away with the wind and thus ensure the spread of the plant.
Red valerian – cultivation and care
The red valerian should be planted in a very sunny, protected and warm location.
Naturally, the red valerian grows in crevices in walls, on rocks and along roadsides. Therefore, it prefers calcareous, very permeable soils with gravel or sand content without waterlogging. But normal garden soil is also possible, as long as it is not too wet.
Planting red valerian
Plant red valerian in spring or late summer at a distance of 45 centimeters. The planting hole should be a bit larger than the root ball. If the soil is very moist, you should use a drainage made of sand or gravel. The long-distance effect is best in small groups. You will need about six plants per square meter (10 sq ft) for an extensive planting.
The red valerian is sensitive to waterlogging in the soil, which is why it should be grown in a location with well-drained soil or in the vicinity of sunlit dry stone walls and rock gardens. Nevertheless, the soil must not dry out completely. During longer periods of dryness, a daily, economical watering may be appropriate during the flowering period. However, this should only be done in the morning and evening hours.
The red valerian is very undemanding. Initial fertilization in spring with ripe compost stimulates growth. Further fertilization can be dispensed with.
If you want to avoid self-seeding, you should cut back the umbels after flowering, which often results in a second flowering in September. Otherwise, the above-ground withered plant remains are cut off near the ground in late autumn or spring.
A mulch layer of gravel or chippings keeps the heat in the soil and stimulates the root growth of the red valerian.
So that the perennials do not fall apart when they grow older, they should be divided every three years. To do this, dig them up in autumn and divide them with a sharp spade. However, since the spurge is a taproot, it can happen that the sections do not grow properly.
The red valerian is extremely vigorous and propagates reliably in the garden by self-sowing. If pink and white plants are combined in a bed, the seedlings will be countless shades of color. Older plants can also be propagated in autumn by division, with more reliable seeding.
Diseases and pests
As a rule, the red valerian does not have to deal with diseases or pest infestation.
The Centranthus species have no problem with frost down to -20 °C / -5 °F due to the wintering in the ground. Around the winter, however, the following factors must be considered:
- Seed by September at the latest, so that the young plants get through the winter well
- choose locations with as much sunshine as possible
- cut off the wilted plant parts in autumn and cover them with a layer of mulch
Use in the garden
In the sunny perennial bed and in the rock garden, the red valerian sets colorful accents alongside yarrow and stonecrop. But it is also a good solution for planting on gravel slopes, stairs, south-facing balconies, roof terraces or for greening roofs. Especially the white flowering red valerian is a popular rose companion. The plant is also suitable as a cut flower.
Centranthus ruber ‘Coccineus’ has bright purple flower umbels, which have a light fragrance. The variety ‘Albus’ has white flowers.