What soil does Delphinium grow in?

It tolerates these soils: average garden soil, calcareous.

Hardy down to -40 °C (USDA zone 3, RHS H7). It gets through winter in every part of the country.

When does Delphinium flower?

Flowering: June–July, blue, purple, white, pink.

How much water does Delphinium need?

Water need: medium. Drought tolerance: low.

Delphinium

Delphinium × cultorum

Delphinium (Delphinium × cultorum) is a perennial. Light: full sun, part shade. Hardy down to -40 °C. Drought tolerance: low. Toxic to dogs, cats and children. Sold in local shops from about €5.90.

Illustration of Delphinium — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

The classic back-of-border perennial for summer: tall, dense flower spikes in shades of blue, purple, white and pink rise above deeply cut foliage, and they make excellent cut flowers. The groups differ a lot: low Magic Fountains types stay around 1 m, the looser Belladonna group reaches 1 to 1.5 m, and Elatum and Pacific hybrids grow to 1.5 or beyond 2 m, so check the final height before you buy. It wants rich, moist but free-draining soil, shelter from wind and staking; cut it to the base after the first flowering, feed and water it, and it often flowers again in early autumn. All parts are highly poisonous.

Watch out for

A demanding plant: tall varieties must be staked or wind and heavy rain will flatten them. Slugs and snails eat the emerging shoots in spring, powdery mildew, leaf spots and grey mould are common in summer, and the crown rots in poorly drained soil or when planted too deep. In Central Europe it copes badly with hot, dry summers and is short-lived (often only 2 or 3 years), so it needs afternoon shade and regular watering; Pacific hybrids are also less winter-hardy here and flop more easily than Elatum group varieties, while the Belladonna group takes heat better.

Key facts

Light: Full sun, Part shade
Water need: Medium
Care: High
Size after 10 years: 1.5 m × 60 cm
Hardiness: down to -40 °C
Foliage: Deciduous
Flowering: J F M A M J J A S O N D June–July, blue, purple, white, pink

Group	Perennial
Light	Full sun, Part shade
Size after 10 years	1.5 m × 60 cm
Ultimate size	0.8–2 m × 45–90 cm
Hardiness	down to -40 °C (USDA 3, RHS H7)
Soil	Average garden soil, Calcareous
Foliage	Deciduous
Flowering	June–July, blue, purple, white, pink
Water need	Medium
Drought tolerance	Low
Maintenance	High
Root aggressiveness	Low
Suckering	no data
Spreading	Low
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	60 cm
For dogs	Toxic
For cats	Toxic
For children	Toxic
Typical price	from about €5.90

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Sizes and prices available

The same plant is sold as a small pot and as a specimen several metres tall, and the price follows. Prices are rounded and for guidance only.

Size	Typical price
size not stated	approx. €5.90

Frequently asked questions

Data updated: October 13, 2026 · How our data is made

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