Antirrhinum majus Seeds | Giant Tetra Snapdragon
LATIN NAME: Antirrhinum majus
COMMON NAME: Giant Tetra Snapdragon
Plant Profile
Snapdragon is a short-lived perennial from rocky ground in Spain, Morocco and southern France, grown in gardens as a hardy annual. The Giant Tetra strain belongs to the tall cut-flower class: plants reach 75-90 cm on sturdy stems, with lance-shaped leaves and dense spikes of large, hooded florets in a wide colour range from white through yellow, pink, bronze and deep red.
The flower is built as a trap. The lower lip forms a landing platform and the two lips are pressed together until a heavy bee lands, at which point the lip springs down and the bee is dusted with pollen on its back. Bumblebees are heavy enough to work the flowers; honeybees usually are not, and often bite through the base of the corolla for nectar instead.
Tetraploid strains such as this one carry double the usual chromosome complement, which shows in thicker stems, larger florets and heavier substance in the petal. Plants flower from June until the first hard frost if they are cut regularly, and they hold colour better in cool weather than in the heat of high summer.
Science & Biotechnology
Antirrhinum majus is one of the classical model organisms of genetics. The snapdragon was used by Erwin Baur and later by Rosemary Carpenter and Enrico Coen to work out how floral symmetry is built, and the CYCLOIDEA and DICHOTOMA genes identified in this species are now the standard explanation for the difference between a symmetrical flower and the two-lipped shape seen here.
The tetraploid condition in this strain is the result of colchicine treatment or of unreduced gametes in breeding lines, and it changes more than size. Tetraploids have thicker leaves, larger stomata, a slightly coarser texture and a tendency to set less seed per capsule, which is why seed yield per plant is lower than in diploid strains even though each floret is bigger.
Snapdragons are also the main host of snapdragon rust, Puccinia antirrhini, which forms raised brown pustules on the underside of leaves in humid weather. Breeding lines differ in susceptibility, and good air movement does more than any spray.
Uses & Benefits
This is a cut-flower variety first and a border plant second. Stems are harvested when the lowest two or three florets are open and the rest are in bud, and they last seven to ten days in water, longer in a cool room. The colour range makes the strain useful for wedding work, where a single batch can supply several tones.
In the border, tall snapdragons need a sheltered spot and a stake or a grid, since a wet storm will flatten them. They suit the back of a cottage-garden border, a cutting patch and large containers, where the scent, which is faintly sweet and strongest in the evening, can be appreciated. Bees and bumblebees work the flowers steadily.
Growing from Seed
Sow on the surface from January to March, since the seed needs light; press it into moist compost and do not cover. Germination takes ten days to two weeks at 18-20°C. The critical detail is temperature after germination: grow the seedlings on at 12-15°C, because warm, soft growth produces plants that stretch, fall over and flower late.
Plant out after the last frost at 25-30 cm apart in full sun and well-drained soil enriched with compost. Pinch the growing tip at the sixth leaf for bushier plants and more stems, or leave it for earlier single spikes. Water at the base, feed every fortnight once flowering starts, and cut stems regularly to keep new ones coming. Save seed only from isolated plants, since bees cross the colours freely.
Our Take
The most reliable cut flower in the catalogue for a cool climate, and one that pays for its space from June to October if you keep cutting.
Related Reading
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