Use with caution
All parts of delphinium are very poisonous - they contain diterpene alkaloids that are toxic to people, dogs, cats, and livestock, with the young foliage and seeds the most dangerous; eating it can cause vomiting, weakness, and serious heart and nervous-system effects. Plant it where pets and children will not graze it, and never eat any part.
Delphinium elatum 'Blue Bird'
flowerBlue Bird is a classic Pacific Giant delphinium, the plant that defines the romantic English border. It sends up towering, densely packed flower spikes four to six feet tall in early summer, lined with large, clear sky-blue flowers each centered with a contrasting white eye known as the bee. Few perennials match its vertical drama or its pure blue color. Delphiniums are, however, demanding and often short-lived: they crave rich soil, full sun, and cool summers, dislike heat and humidity, and their tall hollow stalks must be staked against wind and rain. Cut back after the first bloom, they often rebloom in late summer. They are the centerpiece of the cottage and cutting garden where summers stay cool.
Sun
full sun
Water
Every 5 days
Bloom
~55 days
Difficulty
medium
Lifecycle
perennial
Comes back every year
Spacing
18-24 in. apart
Planting Depth
Set the crown at the soil surface (never deep); ensure sharp drainage
Soil pH
6.5-7.5
Soil Type
Fertile, humus-rich, well-drained
Hardiness Zones
Zones 3 – 7
When to Fertilize
In spring as growth begins and again after the first bloom
Fertilizer
Balanced fertilizer or compost
Grow delphiniums in full sun (with a little afternoon shade in hot climates) in fertile, humus-rich, consistently moist but very well-drained soil; they perform well in neutral to alkaline ground and feed heavily. Crucially, do not plant them too deep and never let them sit in wet soil, or crown rot will set in. They are hardy in zones 3 to 7 and are not suited to the hot, humid summers south of zone 7, where they fizzle. Stake the tall stalks early, before they need it, and shelter them from strong wind. After the first flush fades, cut the spent spikes back to the basal leaves to encourage a second, lighter bloom in late summer. Feed in spring and again after the first bloom, and divide or replace plants every few years as they are short-lived.
🌼 Have a different variety?Cultivars of the same species usually share the same basic care — they differ mainly in flower color, height, and bloom form, not in how you grow them. So this guide still applies even if your exact variety isn't the one shown.
Direct sow
Apr 15
Projected first bloom
Jun 9
Good neighbors that attract beneficial insects or deter pests
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
Devour the tender new spring shoots - hand-pick at night, set traps, and clear debris around the crowns, especially as growth emerges
Like slugs, they shred new growth - trap or hand-pick and keep mulch back from the crown
A white film in humid or crowded conditions - give full sun and airflow, space plants well, and avoid wetting the foliage late in the day
The main killer - caused by wet, poorly drained soil or planting too deep; ensure sharp drainage and set the crown at soil level
Delphinium is a magnificent cut flower - cut the spikes in the cool morning when the lower two-thirds of the florets have opened, and they make a dramatic tall accent in arrangements. In the garden the essential tasks are staking the stalks before they flop and cutting the whole spike back to the basal foliage once the flowers fade, which both tidies the plant and often triggers a second flush of bloom in late summer. Handle with care and wash up afterward, since all parts are poisonous.
An ornamental perennial grown for its dramatic blue spires and as a premier cut flower. The flowers are visited by bees and hummingbirds, but every part is poisonous, so its value is purely ornamental - do not let it be eaten.
All parts of delphinium are very poisonous - they contain diterpene alkaloids that are toxic to people, dogs, cats, and livestock, with the young foliage and seeds the most dangerous; eating it can cause vomiting, weakness, and serious heart and nervous-system effects. Plant it where pets and children will not graze it, and never eat any part.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.