Delphinium – Care Guide

Delphiniums are celebrated for their vibrant summer blooms, which boast beautiful shades of white, blue, pink and purple.

These perennials are prevalent in both cottage-style gardens and cutting gardens, but in order to grow best, they require a good deal of attention.

Delphinium is a genus comprising over 300 species. Certain species are annuals, while others come in the shape of biennials or perennials.

Some are extremely easy to grow from seed, and others thrive better when grown from a cutting.

Delphinium – Care Guide


Basic care

Despite being a favourite of many green-fingered connoisseurs, Delphinium plants do require the correct care in order to grow to their full potential.

For best results, opt for moist, cool climates, as opposed to hot, dry weather. These perennials are also adverse to sudden wind or rain, and as such, require staking.


To encourage growth, choose fertile, well-drained soil and place Delphinium plants in an area that gets both full sunlight and shade.

It’s important to choose a location that is sheltered from strong winds. For best results, plant in the month of spring, using just two to four inches of compost. Dig a hole that measures twice the diameter of the plant’s container, and ensure the top of the root ball is in line with the soil.

This alkaline-loving perennial enjoys lime, wood ashes, or a mixture of the two placed over the soil come spring.

You should insert supports when the Delphinium plants reach 12 inches in height and this is usually no later than mid-spring. Use twiggy, brushwood supports to stake the low-growing perennials, and sturdy stakes, for the taller, large-flowered delphiniums.


The soil should not be allowed to dry out. If rainfall is less than one inch per week, add additional water to your Delphinium plants.

However, always avoid overwatering as this can cause root rot. To encourage good-quality flower spikes, use a balanced liquid fertiliser. This should be applied every two to three weeks.



When pruning Delphinium plants, leave a minimum of two or three shoots on young plants, and five to seven shoots on well-established Delphinium plants.

You can deadhead plants by removing any disbursed flower spikes and flowering side shoots from the Delphinium. This will promote a healthy plant and new growth.

Post blooming, cut flower stalks to the ground. This will encourage new, smaller, flower stalks to develop. These new shoots are able to withstand cold days and light frosts. If you wish to replant Delphiniums, you will need to divide them in the spring. The next step requires you to discard the old heart, and remove and replant the new little plants, which appear around the outside of the clump.

Pests and diseases

Delphinium plants are susceptible to a number of pests and diseases, including common snails and slugs, and cyclamen mites. Other ailments comprise of southern blight, fungal spots, powdery mildew, white rot, leaf smut, crown and root rot and grey mould. It’s important to learn how to spot the signs and act quickly if you wish to rescue your plants.

Slugs are a major curse to Delphinium plants. To rid your plant of these unwanted pests, use a homemade garlic drench. Simply boil two pints of water with crushed garlic cloves. Heat for half an hour and then strain the mixture into a bottle. The fusion should be kept in a cool place. When you need to use it, add two teaspoons to a gallon of water and apply to plants once a week.

Storage and harvest

This graceful bloom is great for a cutting garden. If you transfer blooms into a shed or the warmth of the house, they will bloom again. To make the flowers last longer once cut, create a homemade flower preservative consisting of sugar plus lemon juice and bleach.


Recommended Varieties of Delphinium

There are a number of varieties of Delphinium to choose from, including dwarf-sized Delphiniums, medium-sized Delphiniums and tall versions, which can reach an impressive height of six feet or more.

Belladonna Group: These variants come in the shape of upright, loose and branching perennials, boasting single flowers, which can reach a height of three to four feet. One of the more popular variants comes in the shape of the ‘Blue Bee’ – a Belladonna boasting clear blue flowers with delicate white centres.

Elatum Group: This version is one of the tallest spiked hybrids in existence – in fact, it can grow to six feet or more. One of the prevalent variants is the ‘Blue Nile’ – a medium-sized plant with vibrant, semi-double and mid-blue flowers – all of which feature white centres, which are nicknamed bees. Another variant, which is larger in size, is ‘Bruce’ – a tall Elatum brandishing purple, violet, semi-double flowers, which appear paler towards the centre, and house brown bees.

Pacific Hybrids: Although they’re not quite as tall, these Delphinium variants are similar to the Elatum Group. This hybrid, although short-lived, is often grown as biennials or annuals. ‘King Arthur’ is another popular Delphinium plant, which features plum flowers with white bees. The most impressive feature of this variant is the tall flower spikes, which measure between five and six feet.

Delphinium ‘Celebration’: This upright perennial has spikes measuring an astounding 65 cm in length. On top of this, this specie boasts numerous double, cream flowers and an abundance of side branches.

Delphinium ‘Clifford Sky’: This tall perennial boasts semi-double, pretty sky blue blooms with white eyes. The flowers measure 7 cm wide and come in the shape of branched spikes that bloom in the summer months.

Useful information

Delphinium seeds and very young Delphinium plants are said to be extremely poisonous. If consumed, they can cause the likes of paralysis, nausea, twitching muscles, and in the worst-case scenario, death.

We hope this guide provides you with all the information you need to care for your Delphinium plants, but if you think we’ve missed something please let us know, as we’d love to share it with our readers.

Sources: almanac.com

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Lily Calyx is our in-house flower whisperer, an expert on all things botanical and an enthusiastic orchids collector. She loves discussing the insights of the secret world of flowers, shares her gardening tips and hacks and moons over the latest additions to Serenata Flowers flower range. Ask Lily anything about flowers and we can guarantee she will have the answer.

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