Delphinium

the stars of any combination

Delphiniums

Full sun to light shade; average to moist but well-drained soil

Delphiniums (Delphinium) aren’t particularly distinctive in leaf, but in bloom, they tend to be the stars of any combination. Classic favorites include Elatum Group delphiniums, such as the 4- to 7-foot-tall Pacific Hybrids, with dense, columnar or tapering bloom spikes, and the 3- to 4-foot-tall Belladonna Group hybrids, with looser, branching bloom spikes and lacier leaves. They’re generally best in Zones 3 or 4 to 7 but can go as far sound as Zone 10 where summers don’t get too hot. The New Zealand Hybrids, such as the New Millennium strains, offer the dramatic spires of those older favorites but on sturdier-stemmed plants that are more tolerant of heat and humidity.

Selections of Chinese delphinium (D. grandiflorum, also sold as D. chinensis), such as ‘Blue Butterfly’ and ‘Blue Mirror’, are also a bit more heat tolerant (Zones 3 to 8), but they tend to be short lived, often blooming for just a year or two. They’re also quite compact—in the range of 12 to 30 inches.

Color Considerations

Blue and purple-blue delphiniums are outstanding in “all-blue” or mostly blue borders with other flowering perennials in the same color range. Just keep in mind that pure blue delphiniums may not look good right next to lavender-blue companions, such as Frikart’s aster (Aster × frikartii).

Delphiniums of all sorts are gorgeous with white flowers, like those of Shasta daisy (Leucanthemum × superbum); pink-flowered partners, such as purple coneflower (Echinacea purpurea); and a wide range of yellows. For a high-impact combination, try rich purple or blue delphiniums with vivid orange, scarlet, or red flowers, like those of Oriental poppy (Papaver orientale) or ‘Totally Tangerine’ geum (Geum).

A Perfect Match

I’ve been hearing great things about the New Zealand Hybrids: They sound like an excellent choice for those of us who struggle with growing the classic hybrid delphiniums. Until I can try them for myself, I’ll stick with annual larkspur (Consolida ajacis) when I want delphinium-like blue, pink, or white spires in an early-summer combination. Like their perennial relatives, they’re particularly pretty rising out of a cloud of tiny blooms, like those of baby’s breath (Gypsophila paniculata).

Shapes and Textures

The very vertical, tall delphiniums pair well with large, bushy partners, such as goatsbeard (Arunucus dioicus) or shrub roses, which will remain to fill the space when the delphiniums are done blooming. More-compact hybrids and the Chinese delphiniums work well closer to the front or middle of the border, contrasted with mounded companions, such as coreopsis (Coreopsis) and hardy geraniums (Geranium).

Both the strongly spiky delphiniums and the more open Belladonna and Chinese delphiniums work well with a range of other bloom shapes, from big-and-bold alliums (Allium) and Oriental poppy (Papaver orientale) to daisy-form flowers. They also look terrific with spiky plumes, like those of astilbes (Astilbe).

Seasonal Features

In most areas, delphiniums begin blooming in late spring to early summer, just in time to join many other classic border perennials, including irises, lupines (Lupinus), and peonies, as well as roses. They usually continue into midsummer, at least, so you can also match them with summer favorites, such as daylilies (Hemerocallis), echinaceas (Echinacea), hollyhocks (Alcea rosea), and true lilies (Lilium).

Bloom Buddies

Marvelous Matches for Flowering Combos

Delphiniums (Delphinium) love sun in the cooler parts of their growing range but often appreciate afternoon shade or light all-day shade south of Zone 5. They thrive in compost-enriched soil—ideally on the neutral to slightly alkaline side—that stays somewhat moist. Below are just a few compatible companions whose bloom times overlap with delphiniums.

Bellflowers (Campanula)

Carolina phlox (Phlox carolina)

Catmints (Nepeta)

Coreopsis (Coreopsis)

Daylilies (Hemerocallis)

Foxgloves (Digitalis)

Irises (Iris)

Lady’s mantle (Alchemilla mollis)

Meadow rues (Thalictrum)

Peonies (Paeonia)

Perennial salvias (Salvia)

Pincushion flowers (Scabiosa)

Rose campion (Lychnis coronaria)

Summer phlox (Phlox paniculata)