Delphinium Seeds | White
LATIN NAME: Delphinium
COMMON NAME: Delphinium
Plant Profile
White delphiniums are selected within the tall elatum hybrids for a clean, unmarked petal and a strong upright stem, because florists want a spike that stands straight in a tall jar without a single blemish to catch the eye. Cultivars such as the white form of the Pacific group are the result of decades of line breeding for that exact habit, and the flower is a staple of summer wedding work for the same reason.
Blue delphiniums owe their colour to delphinidin, an anthocyanin pigment; the white sorts simply lack it in the petal, leaving the pale base colour showing. That absence is why a white bloom can turn faintly green or cream as it ages rather than deepening, and why it shows every speck of pollen or rain spot, which is exactly what makes it both beautiful and demanding in the border.
White flowers are unforgiving in the garden, and the plant’s own biology adds to the trouble, since the pale petals announce every blemish and the tall stem invites every splash of mud.
Move plants to their final spot once they show four or five true leaves and stand about fifteen centimetres, setting the crown shallow so the stem base stays dry and the plant resists the rot that topples young delphiniums. Space the young plants so air moves between them, which is the single best defence against the mildew that loves a crowded row.
The white spikes are heavy when in full flower, so run a line of twine or set individual canes before the stems lean, because a delphinium that flops rarely stands again straight. Tie loosely and check weekly, since a snapped stem ends a whole season’s spike at once and the plant puts its energy into a later, shorter side shoot instead.
Science & Biotechnology
Every part of a delphinium carries diterpene alkaloids such as methyllycaconitine, concentrated in the seed and young leaf, and the plant is toxic if eaten, a fact well known to livestock keepers who fence their cattle away from wild larkspur. Gardeners should wear gloves when handling large amounts of foliage and keep the cut stems away from children and pets.
Uses & Benefits
The modern tall delphinium traces to the Pacific hybrid line developed in California in the mid twentieth century, later refined by New Zealand breeders into the New Millennium series that carries the white forms prized by cut-flower growers. White selections were kept separately because they needed the most rigorous roguing to stay pure, and a single blue floret in a white spike ruins the whole stem for the trade.
Growing from Seed
In floristry the white spike is a backbone for summer arrangements, paired with roses and foliage because its height and neutral colour let other blooms sit around it without fighting for attention. Condition the stems in deep water overnight and the open flowers last remarkably well in the vase, and the same pale spike is the making of a moon garden that glows after dark.
Sow the large, angled seed on a fine loam-and-sand mix and cover lightly, then keep cool and just moist; fresh seed gives the best stand because the embryo loses vigour once the seed dries for a season. Prick out the seedlings when they carry their second true leaf and grow them on in a bright, airy place where the air moves freely.
White-flowered sorts show powdery mildew faster than the blues because the pale petal and leaf hide nothing, so water at the base, thin the air with wide spacing, and strip the lower leaves if the stem base looks crowded. A soft soap spray on the leaves keeps the worst of the season’s fungus at bay without marking the flowers, and a clean leaf is the best backdrop for a clean white bloom.
Our Take
I grow white delphinium at the back of the border where its pale spires catch the low sun, and I keep annual larkspur in front for a lighter echo of the form. It sits naturally beside columbine and clematis tangutica, fellow members of the wider buttercup circle.
Related Reading
Gardeners who grow Delphinium often pair it with these related subjects: