Delphinium produces tall showy spikes of brightly colored flowers in summer. Blooms come in a range of colors—blue, violet, pink, white, or two-toned.
The delphinium’s tall wand of flowers emerges from a low mound of foliage. Columns of blooms grow from 3 to 6 feet tall or more.
Delphinium does not tolerate wind, heat, drought, or poorly drained soil. It grows best if it gets shade during the middle of the day.
Get to Know Delphinium
- Plant type: Perennial
- Growing zones and range: 2-7; grow as an annual in Zones 2-7; grow as a perennial in Zones 6-7 where summers are cool.
- Hardiness: Good choice in cool summer regions
- Height and width: 3 to 7 feet (0.9-2.1m) tall; 1 to 3 wide
- Flowers: Intensely blue flower spikes, also light blue, lavender, pink, purple, red, and white
- Bloom time: Early summer
- Uses: Good addition to mixed borders
- Garden companions: Shasta daisy, veronica, sunflower, Joe-Pye weed, anise, hyssop, fragrant bugbane, ornamental grasses.
- Botanical name: Delphinium elatum
- Common name: Delphinium
Where to Plant Delphinium
- Grow delphiniums in full sun.
- Plant delphiniums in humus-rich, moist soil.
When to Plant Delphinium
- Set established plants in the garden in spring.
Planting and Spacing Delphinium
- Space delphiniums 1 to 3 feet (30-91cm) apart.
How to Water and Feed Delphinium
- Keep the soil evenly moist when growing delphiniums. Do not let the soil dry out.
- Fertilize delphiniums every 6 to 8 weeks with an all-purpose fertilizer.
- Mulch around delphiniums to conserve soil moisture.
- Delphinium is prone to disease where summers are warm.
- Stake delphiniums when they reach 18 inches (45cm) tall.
- Remove spent flowers to encourage new blooms.
- Delphiniums are susceptible to attach by mildew, slugs, and snails.
Delphinium Varieties to Grow
- Pacific hybrids grow to 7 feet (2.1m) tall.
- ‘Connecticut Yankee’ grows 2 to 3 feet (0.6-0.9m) tall and is heat resistant.