Blue Rocket

How to grow Blue Rocket

Written by the GardenDecoded editorial team · Last reviewed 21 July 2026 · Written for UK gardens · How we research our guidance

Planting

Plant in autumn or spring in ground that stays reliably moist through summer. It takes more shade than most tall perennials, which makes it useful at the back of a north-facing or woodland-edge border. Mulch after planting to hold moisture.

Pruning

Cut flowered stems down after blooming to tidy the plant, or leave them if you want seed. Remove all top growth once it dies back in late autumn. Tall stems in exposed positions benefit from staking early in the season.

Propagation

Divide the tuberous roots in late autumn or early spring, wearing gloves. Division is best done every three or four years. Seed is possible but slow, and germination is erratic without a cold period.

Pests and diseases

Powdery mildew in dry summers, and slugs on emerging spring shoots. Aphids can build up on flowering spikes.

Value to wildlife

The hooded flowers are worked mainly by bumblebees, which are strong enough to force their way in, and it flowers at a useful point in mid summer.

Notes

Every part of this plant is well known to be poisonous, including the roots. Check its toxicity information before planting anywhere children or pets have access, wear gloves when dividing or handling the roots, and wash your hands afterwards.

This guidance was researched and written by GardenDecoded — see our editorial policy for how guides are checked and reviewed.

Other names for this plant

These names have all been used for Aconitum napellus but are no longer the accepted name. You may still meet them on old labels, in books, or in nursery catalogues.

Others in Aconitum