delphinium 'Rosemary Brock'

Grow in a fertile, well-drained soil in full sun; shelter from strong winds and stake well. Apply a balanced liquid every couple of weeks in the growing season. For the best flower spikes thin shoots when 7cm high to leave a minimum of 2-3 shoots on young plants and 5-7 shoots on established plants

Deadhead by cutting spent flower spikes back to small flowering side shoots. Cut down all growth to ground level after it has withered in autumn

Propagate by taking pencil thick basal cuttings in early spring

May be attacked by slugs, snails, leaf miners and caterpillars

May be subject to powdery mildews, delphinium black blotch, crown rot and a virus