Free Shipping on orders over £60

Plant Care

How to Grow Delphiniums

Delphiniums, towering up to 2 metres, bloom in midsummer with hues from blue to red. Sow early, plant in May, and enjoy their grandeur alongside roses and peonies. Perfect for bees and vases, these cottage garden staples with a rich British legacy, named after the Greek 'delphinos', bring historical elegance to gardens.

Jump to:
Herboo Seeds

Grow Delphiniums From Seed

Growing delphiniums from seed is a great way to produce a stunning floral display the following year. Start by sowing seeds under cover in a seed tray with peat-free compost, watering before sowing to prevent seed displacement. Scatter the seeds thinly and cover them with a fine layer of vermiculite, remembering to label your trays. When seedlings develop three sets of true leaves, transfer them into individual 9cm pots filled with peat-free compost and grit, keeping them labelled. Let them mature before planting them out in May or June, after gradually acclimating them to outdoor conditions. Seeds can be sown from February to June or in early autumn and should be kept at 50°-60°F. Alternatively, propagate by taking basal cuttings in spring. Select new shoots, trim the top foliage after placing them into a pot with compost and perlite, and maintain moisture with regular misting or a polythene bag cover. Whether from seeds or cuttings, delphiniums promise to elevate your garden with their impressive blooms.

Sow under cover with a fine layer of vermiculite.

What Delphiniums Needs

Protection iconFeeding iconWatering icon

Protection: Staking is vital for delphiniums; any strong wind or heavy rain will flatten them. Feeding: Feed delphiniums twice in summer, and again in autumn. Use slow-release and seaweed fertilisers. Watering: Water regularly during the summer months.

Growing Delphiniums Across the Season

Spring icon


Sow delphinium seeds indoors in spring for blooms next year; transplant seedlings in late spring.

Summer icon


Stake young delphiniums; water and feed often. Cut June blooms to the ground for more flowers later.

Autumn icon


Plant delphiniums for next summer; feed as they wilt for future robustness.

Winter icon


Choose new delphinium varieties for the upcoming season's sowing and growing period.

Delphiniums S.O.S.

At the first sign of new growth in spring, safeguard young delphinium shoots from slugs and snails using methods like garlic drench, organic pellets, or slug-specific biological control. To prevent powdery mildew, ensure the soil remains moist, especially during dry spells. If rust appears, identified by rust-coloured spots on leaves, promptly remove and dispose of the infected foliage. Additionally, watch for delphinium black blotch, a bacterial issue causing large black spots on leaves, more prevalent in damp summers. Infected plants should be removed entirely to stop the disease from spreading.

SVG Icon

Keep soil moist to avoid mildew.

Your bag is empty.
Here is a flower.

Herboo Seeds
Shop all