About
A deciduous, herbaceous perennial that reaches approximately 1.7m in height when in flower. It forms an even mound of fresh to dark green, incised leaves and flower stems of gentian blue flowers with a white centre, in summer.
About the genus
Delphinium can be annuals, biennials or perennials, with palmately lobed basal leaves and showy bowl-shaped flowers in spikes, racemes or panicles
Growing conditions
SunlightFull sun
Soil typeChalk, Loam, Sand
Soil pHAcid, Neutral, Alkaline
Soil moistureMoist but well-drained
AspectWest-facing, South-facing, East-facing
ExposureSheltered
UK hardinessH5
Plant details
Plant typeHerbaceous Perennial
HabitColumnar upright
FoliageDeciduous
Height1.5-2.5 metres
Spread0.5-1 metres
Time to full height1-2 years
Suggested usesCity and courtyard gardens, Cottage and informal garden, Wildlife gardens
ToxicityHumans/Pets: Harmful if eaten. Wear gloves and other protective equipment when handling. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Care notes
CultivationGrow in fertile, well-drained soil in full sun. Shelter from strong winds and provide support (see staking perennials). Divide every 2-5 years to maintain vigour. See staking perennials and delphinium cultivation for further advice
PruningDeadhead spent flower spikes back to fresh flowering side shoots and cut back to ground level in late autumn.
PropagationPropagate by division or by basal softwood cuttings in spring
Pest resistanceMay be susceptible to aphids, earwigs, delphinium leaf miner, delphinium moth caterpillars, slugs, snails and caterpillars
Disease resistanceMay be susceptible to Powdery mildews, delphinium black blotch, crown rot and viruses