Spoorbloem

Centranthus ruber

Engels: Red valerian

perennialCaprifoliaceae

Spoorbloem (Centranthus ruber) is a perennial from the Caprifoliaceae family that grows up to 90cm tall. This plant thrives in full sun to partial shade and requires low maintenance. Blooms in late spring and early summer and summer and late summer with pink, red, white flowers and attracts bees and butterflies.

Hoogte

60–90 cm

Breedte

40–60 cm

Zonligging

full sun, partial shade

Waterbehoefte

low water needs

Grondsoort

sandy soil, loam, chalky soil

Onderhoud

low maintenance

Bloeitijd

late spring, early summer, summer, late summer

Bloemkleuren

pink, red, white

Ecologische waarde

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Verzorgingskalender

Taak	Jan	Feb	Mrt	Apr	Mei	Jun	Jul	Aug	Sep	Okt	Nov	Dec
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Care tips

Planting

Centranthus ruber, commonly known as red valerian or spoorbloem, thrives in full sun or partial shade and is remarkably unfussy about soil. It performs best in well-drained sandy, loamy, or chalky soils and actually prefers lean, alkaline conditions—avoid rich, heavy ground that stays wet. The plant is ideal for dry banks, gravel gardens, walls, and coastal sites where many other perennials struggle. Plant spoorbloem in March, April, or May for establishment before summer, or in September and October to give roots time to settle before winter. Space plants 45 cm apart to allow for their mature spread of 40–60 cm. Dig a hole slightly larger than the root ball, loosen the soil at the base, and position the crown at the same level it sat in the pot. Backfill with excavated soil—there's no need to add compost or manure, as spoorbloem dislikes overly fertile conditions which encourage floppy growth at the expense of flowers. Water in thoroughly after planting to settle roots, then water sparingly. Once established, Centranthus is drought-tolerant and needs little supplementary watering except during prolonged dry spells in the first season. Mulching is generally unnecessary and can retain too much moisture around the crown. If planting in autumn, avoid waterlogged sites over winter. Spoorbloem often self-seeds freely in cracks and crevices, so if you want a more naturalistic effect, allow a few seedheads to mature after the first flush of flowers.

Pruning

Spoorbloem flowers from late spring through to late summer, producing dense clusters of small tubular blooms on upright stems. To keep plants tidy and encourage a second flush of flowers, deadhead or cut back hard in August after the main flowering period. Use secateurs or garden shears to trim the whole plant back by about half to two-thirds, removing spent flower stems and any straggly growth. This August prune stimulates fresh basal foliage and often a modest second flowering in early autumn, while also preventing excessive self-seeding if that's a concern in your garden. In March, carry out a light tidy-up to remove any winter-damaged stems and old foliage. Cut back dead or frost-damaged growth to just above emerging new shoots at the base. Spoorbloem is semi-evergreen in milder winters but can look tatty by late winter, so this spring prune refreshes the plant and promotes vigorous new growth. Avoid cutting into woody older stems at the base unless you're rejuvenating a very old clump, as Centranthus can be slow to reshoot from hard, bare wood. The plant naturally forms a bushy, somewhat sprawling habit and doesn't require complex shaping. If it becomes too large or floppy, especially in richer soils or shadier spots, cut it back more severely in March. Spoorbloem is short-lived as perennials go, typically lasting four to six years, so take cuttings or allow some self-seeding to maintain a succession of young plants.

Maintenance

Centranthus ruber is a low-maintenance perennial well suited to dry, sunny spots. Water sparingly once established; the plant is drought-tolerant and dislikes sitting in wet soil. In summer, water only during extended dry periods—overwatering encourages soft, disease-prone growth. In autumn and winter, natural rainfall is almost always sufficient, and good drainage is more important than moisture. Feed lightly in April or May with a general-purpose granular fertiliser or a handful of blood, fish, and bone around the base of each plant. Avoid high-nitrogen feeds or rich soil amendments, as spoorbloem flowers best in lean conditions. Overfed plants produce lush foliage but fewer blooms and are more prone to flopping. In most garden soils, especially chalky or sandy types, feeding can be skipped altogether without harm. Spoorbloem is fully hardy in zones 5–9 and requires no special winter protection in temperate Europe. In very cold or wet winters, plants may die back to the crown but will reshoot reliably in spring. Mulching is unnecessary and can cause crown rot in damp conditions. Pests are rarely a problem. Aphids occasionally cluster on young shoots in spring; a strong jet of water or an insecticidal soap usually resolves this. Powdery mildew can appear on foliage in dry summers, particularly in crowded plantings with poor air circulation—thin congested clumps and ensure adequate spacing. Spoorbloem self-seeds enthusiastically, especially in gravel or paving cracks. Weed out unwanted seedlings promptly, or embrace the informal, cottage-garden effect they create.