Soil & potting mix

Best soil for Delphinium grandiflorum 'Blue Butterfly' (Delphinium grandiflorum 'Blue Butterfly')

Also called Blue Butterfly delphinium, Chinese delphinium.

More about delphinium grandiflorum 'blue butterfly'

Delphinium grandiflorum 'Blue Butterfly' soil at a glance

Best mix	Fertile, well-drained soil
Light	Direct sun (at least 4-6 hours)
Ideal temperature	-34 to 27°C (-29 to 81°F)
Watering	Every 4-7 days; keep soil moist but well-drained, avoiding extremes

About Delphinium grandiflorum 'Blue Butterfly'

Delphinium grandiflorum 'Blue Butterfly' · also called Blue Butterfly delphinium, Chinese delphinium · flowering

'Blue Butterfly' is a dwarf Chinese delphinium grown for masses of brilliant gentian-blue flowers on airy, branching stems in summer. Far shorter than border delphiniums at 30-40 cm, it suits fronts of beds, pots and gravel gardens, needs no staking, and flowers fast from seed. Like all delphiniums, it is toxic to cats and dogs.

Preferred mix: Fertile, well-drained soil

Watch for — Crown rot in wet soil: Heavy, poorly drained ground rots this short-lived species fast. Plant in sharply drained soil or gritty container mix and avoid winter wet.

Why delphinium grandiflorum 'blue butterfly' needs this mix

Delphinium grandiflorum 'Blue Butterfly' flowers hardest in a rich but free-draining loam — fed enough to fuel the display, open enough that the roots never waterlog.

Flowering is expensive for delphinium grandiflorum 'blue butterfly': producing buds, blooms and seed draws heavily on nutrients and steady moisture, so the soil has to keep delivering all season.
A loam-based mix holds nutrients and water far more evenly than a light peat mix, which means a longer, more reliable flowering period.
It still needs sharp drainage — most flowering plants resent cold, wet feet far more than they resent being a little lean.

For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.

What goes wrong with the wrong mix

The wrong soil is one of the most common reasons delphinium grandiflorum 'blue butterfly' struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:

A thin, hungry or sandy mix gives delphinium grandiflorum 'blue butterfly' weak growth and few, short-lived flowers — it simply runs out of fuel.
A heavy, badly drained soil rots the roots or crown, often over a wet winter, and you lose the plant before it ever flowers again.
Over-rich, high-nitrogen mixes can push lush leaf at the expense of flowers — balance, not excess, is the aim.

Either starving delphinium grandiflorum 'blue butterfly' in a thin mix or drowning it in a heavy, badly drained one. It wants the rich-but-free-draining middle, plus a flowering (higher-potassium) feed in season.

pH — does it matter for delphinium grandiflorum 'blue butterfly'?

Most flowering plants, including delphinium grandiflorum 'blue butterfly', do well around pH 6.0-7.0. A cheap soil test is worth it outdoors; one notable exception is any acid-lover (such as some hydrangeas), where pH directly changes flower colour.

If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.

DIY mix vs a bagged one

A quality bagged compost works for delphinium grandiflorum 'blue butterfly' in pots if you add grit and a flowering feed. In beds, improving the existing soil with compost and ensuring drainage beats any bag.

Drainage and the pot

Free drainage protects the roots and especially the crown over winter — raised beds, grit in the planting hole and never a waterlogged spot. Containers must have a clear drainage hole.

For perennials, refresh the top layer and feed each spring rather than disturbing the roots; for container displays, start with fresh rich mix each season. When the time comes, our repotting guide for delphinium grandiflorum 'blue butterfly' covers the timing and technique step by step.

Delphinium grandiflorum 'Blue Butterfly' soil — frequently asked questions

What is the best soil mix for delphinium grandiflorum 'blue butterfly'?

3 parts good loam or quality peat-free compost : 1 part well-rotted compost or leaf mould : 1 part grit or perlite. Flowering is expensive for delphinium grandiflorum 'blue butterfly': producing buds, blooms and seed draws heavily on nutrients and steady moisture, so the soil has to keep delivering all season.

Can I use normal potting soil for delphinium grandiflorum 'blue butterfly'?

A thin, hungry or sandy mix gives delphinium grandiflorum 'blue butterfly' weak growth and few, short-lived flowers — it simply runs out of fuel. A quality bagged compost works for delphinium grandiflorum 'blue butterfly' in pots if you add grit and a flowering feed. In beds, improving the existing soil with compost and ensuring drainage beats any bag.

Does delphinium grandiflorum 'blue butterfly' need a special pH?

Should I buy a bagged mix or make my own for delphinium grandiflorum 'blue butterfly'?

How often should I refresh the soil for delphinium grandiflorum 'blue butterfly'?

For perennials, refresh the top layer and feed each spring rather than disturbing the roots; for container displays, start with fresh rich mix each season. Free drainage protects the roots and especially the crown over winter — raised beds, grit in the planting hole and never a waterlogged spot. Containers must have a clear drainage hole.