How to prune valerian

Deadhead immediately after flowers fade in early to midsummer; cut back to ground in autumn. Snip off spent flower heads before seed sets — valerian self-sows aggressively. In autumn cut all stems down to the basal foliage rosette. If plants become crowded, divide in spring every 3–4 years.

Deadhead as blooms fade; annual autumn cutback. Valerian is a tall, self-seeding perennial that spreads prolifically if allowed to set seed. Deadhead religiously after flowering to limit unwanted spread — this is the most important pruning task. Cut all stems back to the basal rosette in autumn. Otherwise it needs little attention.

Snip off spent flower heads before seed sets — valerian self-sows aggressively. In autumn cut all stems down to the basal foliage rosette. If plants become crowded, divide in spring every 3–4 years.