How to Grow and Care for Delphiniums in the South
They're striking—and unmistakable. Delphiniums are towering columns of bright blooms that can reliably add a dose of drama to any landscape. They're often found in classic English cottage gardens, and their distinctive blooms are great additions to cutting gardens across the U.S. too. While these flowers have developed a reputation for being finicky plantings in the Southern states—they balk at the heat and humidity of our summers—they're just plain gorgeous, which is why we've figured out ways to keep planting them. Read on to learn how to make delphiniums feel at home in your garden.
Delphiniums get their name from the Greek delphinion, meaning "dolphin," as some species are said to resemble the saltwater swimmers. Delphiniums usually bloom during the spring and early summer months, and they produce tall columns of brightly colored flowers in shades of blue, pink, lavender, yellow, red, and white. The native species are reliably perennial, and some of the striking (though more difficult to tend) hybrid species can be treated as annuals if necessary.
Delphinium or Larkspur?
The genus delphinium includes several species that also go by the common name larkspur, so the names are often used interchangeably. Larkspur is also a common name used for flowers in the genus Consolida, including Consolida ajacis, a relative of plants in the genus delphinium. Both of the genera are part of the family Ranunculaceae.
Why You Should Grow Delphiniums
Aside from the fact that the tall stems of brightly colored blooms are just gorgeous in the garden, certain delphinium species are also known to attract butterflies and bees. In a garden design, they can add visual interest with height, shape, and color. If you have many low-to-the-ground plantings in your cutting garden, consider adding delphiniums for an infusion of vertical variety. While most delphinium species reach heights from 1 to 6 feet tall, some hybrids grow much higher.
Types of Delphiniums
Candle delphinium (Delphinium elatum)
Also known as candle larkspur, this delphinium species blooms in shades including blue, purple, pink, and white. This group is where you'll find many hybrid selections, including the Pacific strain hybrids, which have been known to grow to 8 feet tall. Selections include 'Percival,' which is white with a black center; 'Summer Skies,' which blooms in light blue hues; and 'Blue Bird,' which has bright blue flowers.
Carolina larkspur (Delphinium carolinianum)
This plant is native to the Southeast and Midwest. It has a narrow form and bursts into a heavy showing of blue or white blooms in spring. Afterward, during the summer months, it goes dormant. Prairie larkspur (previously Delphinium virescens), also called white larkspur, is a sub-species that's native from Texas to Canada. It's heat-tolerant and produces tall stalks of delicate, widely spaced white flowers that bloom from spring into summer.
Chinese delphinium (Delphinium grandiflorum, D. chinense)
Also known as bouquet delphinium or Siberian larkspur, this heat-tolerant species produces large, deep blue flowers that grow in bushy masses of loose, asymmetrical formations. Selections include 'Dwarf Blue Mirror,' which grows to 1 foot tall, and 'Tom Thumb,' which grows to 8 inches tall.
Delphinium x belladonna
This delphinium group produces full, dense forms with light and delicate clusters of flowers. Selections include 'Belladonna' (light blue), 'Bellamosum' (dark blue), 'Casa Blanca' (white), and 'Cliveden Beauty' (deep turquoise).
Tall larkspur (Delphinium exaltatum)
Tall larkspur is native to the U.S. and grows north to Pennsylvania and south to Alabama. It produces bright blue flowers and reaches heights of 3 to 6 feet tall. It's both a drought- and shade-tolerant planting.
How to Grow Delphiniums
These plants need rich soil that's very porous, and they do best with regular watering and feeding in a spot where they can receive full sun. Because they grow to considerable heights, these flowers also require staking to ensure stability in the garden. To get them started, per The Southern Living Garden Book, "Delphiniums are easy to grow from seed. In the Middle, Lower, and Coastal South, sow fresh seed in flats or pots filled with potting soil in July or August, and set out transplants in October for bloom in late spring and early summer. In the Upper South, sow seed in March or April and set out transplants in June or July for first bloom by September (and more bloom the following spring)."
According to The Southern Living Garden Book, "If you live in the Upper South, you can set off a burst of delphinium blooms like those you see in English gardens. When new stalks appear in spring, remove all but the strongest two or three, tie to stakes, and apply a bloom-booster fertilizer. After blooms fade, cut stalks nearly to the ground, leaving foliage at the bottom. Fertilize again and you may get a second bloom."
Careful! Delphiniums Are Toxic
All parts of the delphinium plant (especially the very young delphinium plants) are toxic to humans and animals, so take care not to ingest them, and keep them away from children, pets, and livestock.
What flowers are you adding to your garden this year? Let us know your favorite flowers to plant for stunning spring blooms.