How to Grow Delphinium


Delphinium is a genus of about 300 species of perennial flowering plants in the family Ranunculaceae, native throughout the Northern Hemisphere and also on the high mountains of tropical Africa. The genus was erected by Carl Linnaeus in 1753.

Most delphiniums are toxic if ingested and some can be irritating to skin. However, they are very popular ornamental plants in gardens, with many cultivars available.

Delphiniums have been used medicinally for centuries and contain several alkaloids that can be poisonous if taken in large doses. The flowers come in a wide variety of colors, including blue, purple, pink, white and yellow.

The most common species is the Pacific Giant Hybrid (D. grandiflorum), which grows up to 8 feet tall in its native habitat.

The foliage of delphiniums often have a silvery green sheen, and the flowers are highly fragrant.

Delphiniums can be found growing in gardens, meadows, and woodlands, and they are a favorite of hummingbirds and butterflies.

Overview How to Grow Delphinium

Delphiniums thrive in full sun and well-drained soil. They prefer a slightly acidic to neutral pH and will require regular watering during their growing season (which typically lasts from April to September).

If you want your delphiniums to continue blooming for the entire season, deadheading (removing spent flowers) is essential.

Delphiniums are relatively easy to care for and can be propagated by dividing the rootball in spring or early summer. In colder climates, it may be necessary to provide a layer of mulch around the base of the plant in order to protect it from freezing temperatures.

Gardeners should also take extra care when pruning or fertilizing their delphiniums, as too much of either can result in decreased flowering. With proper care, delphiniums will reward you with a beautiful display of colorful blooms for many years to come.

10 Ways How to Grow Delphinium

Soil Preparation

Start by ensuring the soil is well draining and slightly acidic to neutral in pH. Incorporate some organic matter such as compost or manure into the planting area before you begin to plant your delphiniums. If necessary, amend your soil with a slow-release fertilizer and bone meal.

Sun Exposure

Delphiniums require six to eight hours of direct sunlight each day. If possible, choose a location that is sheltered from strong winds so the flowers do not get damaged by them.


Keep your soil moist but not soggy. Too much water can lead to root rot or other diseases. It’s best to water early in the morning or evening when the sun is not too strong.


Delphiniums need a balanced fertilizer once or twice a month during their growing season. Use an all-purpose plant food that is high in phosphorus, such as 10-10-10.


In colder climates, it’s best to cover your delphiniums with a layer of mulch during the winter months in order to protect them from freezing temperatures.


In order to support the tall stems, you may need to stake delphiniums with bamboo poles or other supports. It’s best to install these when the plant is still young and growing actively.


Deadheading spent flowers is essential in order to extend the bloom period. It is best to do this as soon as the petals start to droop or fade.

Pest and Disease Control

Keep an eye out for pests such as aphids and spider mites, which can be treated with insecticidal soap. Planting companion plants near your delphiniums can help deter these pests.


Delphiniums can be propagated by dividing their rootball in the spring or early summer.

Companion Planting

Delphiniums look great when planted with other perennials such as foxglove, columbine, or coneflower. Planting them in groupings will help fill out your garden and provide visual interest.

Overall, Delphiniums are relatively easy to care for and can reward you with beautiful blooms in a variety of colors if given the right conditions.


Delphiniums are a stunning addition to any garden and can be enjoyed for many years given the right care and conditions. They come in a wide variety of colors, have an attractive silvery green foliage, and are heavily pollinated by hummingbirds and butterflies. They thrive in full sun and well-drained soil and require regular deadheading to keep blooming all season long. With proper care, delphiniums will reward you with a beautiful display of colorful blooms for many years to come.

Leave a Comment