Plant 317

Hyacinthus orientalis L. (Asparagaceae)

Florists' hyacinth

Humans manipulate the biology of plants around them; plants respond by adapting, acclimating or dying. Climate change has modified the earliest flowering date of native British plants over the past century. Artificial breeding has produced plants incapable of survival outside the cossetted environs of horticulture, forestry and agriculture. Environmental manipulation means fruits and flowers are available to consumers all year around. One early herald of spring, whose flowering cycle has been manipulated, is the florists' hyacinth.

Forcing, whereby hyacinths are induced to flower at Christmas, involves depriving bulbs of light and warmth for about three months, before growing them on in a bright, cool place before flowering is required. Dutch horticulturalists were using the technique by the 1730s. By the 1750s, the French court had made the practise fashionable and a market was created for elaborate, narrow-necked, water-filled, forcing glasses.

The native distribution of wild Hyacinthus orientalis is the eastern Mediterranean, especially Anatolia; the plants have loose spikes of up to a dozen fragrant, pale blue flowers. Hyacinths, together with tulips, became associated with the Ottoman Court, although gardeners of the Topkapi Palace appear to have known few variants other than some double flowered and pink mutants.

During the eighteenth century, hyacinths became fashionable; florists - the plant geneticists of their day - had become interested in them. By 1739, the bulb merchants Nicolas van Kampen & Sons were offering nearly 400 varieties of hyacinth for sale. In 1752, another grower claimed yellow hyacinths would never be produced; fifteen years later lilac and yellow hyacinths were on the market. By the end of the nineteenth century, thousands of cultivars had been developed, the colours more intense, the spikes denser and the flowers larger than in previous centuries.

Today, most cultivars from the past four centuries of horticultural activity are extinct; the artificial selection of the marketplace has determined which are the best cultivars. The surviving colours range from white and yellow through blue and pink to scarlet. All the variation in the florists' hyacinth comes from within the wild Hyacinthus orientalis; there is no evidence that any other Hyacinthus species, or species in genera related to Hyacinthus, are involved.

When Cyril Darlington, 12th Sherardian Professor of Botany in Oxford's Department of Botany, and colleagues at the John Innes Institution (Hertford), investigated the fundamental behaviours of plant chromosomes during the 1930s and 1940s, their models were the large, distinctive chromosomes of Hyacinthus orientalis.

Further reading

Darlington, CD et al. 1951. The history of the garden hyacinths. Heredity 5: 233-252.

Graine G 2014. Fooling mother nature: forcing flower bulbs for indoor bloom. Virginia Cooperative Extension.

Hu F et al. 2011. Chromosome analysis of five diploid garden hyacinth species. Scientia Horticulturae 131: 82i-87.

Stephen Harris