How to prune helianthus decapetalus 'flore pleno'

Cut back by a third in early summer; deadhead in late summer and autumn; full cut-back in autumn. Reduce stem length by about one-third in early summer with clean secateurs. Remove spent flower heads back to a leaf node or side bud. Cut all stems to the base in autumn.

Height reduction once in early summer; deadhead regularly; hard cut-back once a year. Helianthus decapetalus 'Flore Pleno' (double-flowered thin-leaved sunflower) benefits from cutting back by a third in early summer to keep it upright and compact. Deadhead spent double blooms to extend flowering. Cut the whole clump to the ground in autumn. Divide every 2–3 years as it spreads vigorously.

Reduce stem length by about one-third in early summer with clean secateurs. Remove spent flower heads back to a leaf node or side bud. Cut all stems to the base in autumn.