Delphiniums (larkspur) are iconic, tall-stalked perennials renowned for their dramatic spires of blue, purple, pink, and white flowers blooming in early-to-late summer. Ideal for cottage gardens and as cut flowers, they thrive in full sun and fertile, well-drained soil, generally preferring cool summers and USDA Zones 3–7. They require staking due to their height (up to 6 feet) and are poisonous. 
Key Care & Requirements
Sunlight: Full sun is best (6–8 hours daily), though they appreciate afternoon shade in hotter climates.
Soil: Rich, fertile, and well-drained soil is crucial to avoid root rot.
Watering: Maintain consistent, medium moisture; avoid overwatering.
Maintenance: Staking is necessary to protect tall stalks from wind and rain. Deadhead in summer to encourage a second flush of blooms.
Spacing: Space plants 15-30 cm (approx. 1 foot) apart.
Pests/Diseases: Susceptible to slugs, snails, and powdery mildew. 
Varieties & Types
Delphinium elatum hybrids: Popular tall, classic garden types.
Pacific Giant Series: Tall,, robust hybrids (4–6 ft) often grown from seed.
New Millennium Series: Bred for improved heat tolerance and sturdier stems.
Belladonna types: Generally shorter, with more branched, open flower spikes.
D. grandiflorum (e.g., 'Blue Butterfly'): Compact, bushy types suitable for smaller spaces. 
Key Considerations
Toxicity: All parts of the plant are poisonous, particularly the seeds.
Lifespan: Often short-lived perennials in warmer, humid, or Midwest climates.
Best Companion Plants: Pairs well with roses, lilies, and geraniums.