Pruning Red valerian

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.