Delphiniums, also known as larkspurs, are perennial flowering plants prized for their tall spikes of vibrant blooms. Native to the Northern Hemisphere, these plants thrive in temperate climates and are a favorite in American gardens for their striking colors and vertical interest. Delphiniums belong to the Ranunculaceae family and are available in a wide range of varieties, each with unique characteristics suited to different garden conditions.
The Pacific Giant series is one of the most popular delphinium varieties in American gardens. These hybrids are known for their towering spikes, reaching up to 6 feet in height, and large, semi-double flowers in shades of blue, purple, pink, and white. Pacific Giants prefer full sun and well-drained soil with consistent moisture. They are ideal for cottage gardens and as backdrops in perennial borders. However, they may require staking to support their heavy flower spikes.
A more compact alternative to the Pacific Giants, the Magic Fountains series grows to about 3–4 feet tall, making it suitable for smaller gardens or container planting. This variety produces dense spikes of flowers in rich blues, lavenders, and whites. Magic Fountains are more heat-tolerant than some taller delphiniums, making them a better choice for warmer regions of the U.S. They also attract pollinators like bees and butterflies.
Bred for improved vigor and disease resistance, the New Millennium series is a top choice for American gardeners. These delphiniums grow 4–5 feet tall and feature sturdy stems that reduce the need for staking. The flowers come in a range of colors, including deep blues, purples, and bicolors. New Millennium varieties perform well in USDA zones 3–7 and are known for their long blooming period when deadheaded regularly.
The Belladonna group offers a more relaxed, branching growth habit compared to the towering elatum hybrids. These delphiniums grow 3–4 feet tall and produce loose clusters of single or double flowers in shades of blue and white. Belladonna varieties are excellent for naturalistic gardens and mixed borders. They are also more tolerant of partial shade, though they still prefer well-drained soil.
A dwarf variety, the Connecticut Yankees series grows only 12–18 inches tall, making it perfect for rock gardens or front-of-border plantings. These delphiniums produce abundant, smaller flowers in blue, pink, or white. Unlike taller varieties, Connecticut Yankees are short-lived perennials but often reseed themselves. They thrive in full sun and are more drought-tolerant once established.
The Guardian series is another excellent choice for American gardens, especially for those seeking shorter, more manageable plants. Growing to about 2–3 feet tall, these delphiniums are ideal for windy areas where taller varieties might topple. The flowers are densely packed and come in classic delphinium colors like sky blue, lavender, and white. Guardians are also known for their strong stems and resistance to powdery mildew.
To ensure success with delphiniums in American gardens, plant them in full sun (at least 6 hours daily) and rich, well-drained soil. Amend heavy clay soils with organic matter to improve drainage. Water regularly but avoid soggy conditions, as delphiniums are prone to root rot. Stake taller varieties early in the season to prevent wind damage. Deadhead spent blooms to encourage reblooming and divide clumps every 3–4 years to maintain plant health.
