Larkspur and delphiniums -the quintessential flowers of high summer. Whether grown from seed or planted as perennials, they reward gardeners with one of the most spectacular floral displays of the season.
Few flowers capture the spirit of an English summer quite like larkspur and delphiniums. Rising above herbaceous borders in elegant spires of blue, lavender, pink, white and deep purple, they bring a sense of height, movement and romance that few other plants can match. Whether planted in a traditional cottage garden, a contemporary perennial border or grown specifically for cutting, these classic flowers have remained enduring favourites with gardeners.
Although often confused, larkspur and delphiniums are closely related but distinct plants. Annual larkspurs (Consolida ajacis) are easy-to-grow cottage garden flowers that produce graceful, airy flower spikes, while perennial delphiniums (Delphinium species and hybrids) are larger, more architectural plants that return year after year with proper care. Both belong to the buttercup family (Ranunculaceae) and share the same vertical elegance.
Their popularity lies partly in their unrivalled shades of blue.
Truly blue flowers are surprisingly uncommon in the garden, yet delphiniums produce some of the richest sapphire, cobalt and sky-blue blooms available. Combined with whites, soft pinks and mauves, they create cool, sophisticated colour palettes that pair beautifully with roses, foxgloves, peonies and salvias during the height of summer.
Another reason gardeners treasure them is their ability to add vertical interest. While many summer flowers spread horizontally, delphiniums send towering flower spikes soaring creating dramatic punctuation throughout borders. Annual larkspurs are slightly shorter.
Both are also exceptional cut flowers. Their long stems and elegant spikes bring height and colour to arrangements, while newly opened blooms continue to develop in water.
Growing delphiniums
Delphiniums thrive in fertile, moisture-retentive but well-drained soil. They perform best in full sun, although in hotter parts of the country they appreciate a little afternoon shade.
Space plants generously to improve airflow and reduce the risk of fungal diseases such as powdery mildew.
As growth begins in spring, apply a balanced fertiliser and water regularly during dry periods. Delphiniums are thirsty plants, particularly when producing their impressive flower spikes.
The tall stems almost always require staking. Install supports early, before rapid growth begins, allowing the foliage to hide the stakes naturally as the plants develop.
After the first flush of flowers fades, cut the spent stems back to the base.
Growing larkspur
Annual larkspurs are among the easiest flowers to grow from seed. They dislike root disturbance, so are best sown directly where they are to flower. Seeds germinate readily in cool conditions and often perform best when sown in autumn or very early spring.
Choose a sunny position with well-drained soil. Thin seedlings to around 20–30 cm apart to allow each plant room to develop. Once established they require relatively little attention beyond occasional watering during prolonged dry spells.
Allow some flower spikes to set seed and many gardens will enjoy natural self-sown plants in subsequent years, creating relaxed drifts that suit informal planting schemes beautifully.
Beautiful varieties to grow
Among perennial delphiniums, the famous Elatum Group remains the gold standard for borders. These majestic plants produce dense flower spikes in rich blues, purples, whites and pinks, often with contrasting central “bees” that add further interest.
‘Black Knight’ is a long-established favourite with deep violet-blue flowers and striking dark centres, bringing bold colour to mixed borders.
‘Magic Fountains Sky Blue’ offers the classic delphinium look in a more compact form, making it suitable for smaller gardens while still producing impressive flower spikes.
For pure elegance, ‘Galahad’ bears pristine white flowers that illuminate evening gardens and combine beautifully with silver foliage and pastel companions.
Gardeners seeking softer shades often choose ‘Sweet Sensation’, with delicate lavender-blue flowers held on sturdy stems that perform well as cut flowers.
Among larkspurs, the ‘Sublime’ series offers excellent colour range and reliable performance, while ‘Imperial Giant Mixed’ produces tall, graceful spikes in a delightful blend of blues, pinks, lilacs and whites.
What’s in a name?
Larkspur and delphinium belong to the same family (Ranunculaceae) and share many similarities, leading to overlapping names. However, larkspur is typically an annual with feathery foliage and looser flower spikes, while delphinium is usually a sturdier perennial with deeply lobed leaves and dense, showy flower stalks.
