DAHLIA

DAHLIA

Dahlias are native to Mexico and were known by the Aztecs, who called them “acocoxochitl” and used their tubers as food. Their name comes from the Swedish naturalist Andrea Dahi, but they have also been called “Georgina” in memory of King George III, who highly prized this plant. The Dahlia genus belongs to the Asteraceae (composite) family as do daisies and Chrysanthemums. Their scientific name “Dahlia variabilis” indicates the numerous varieties of shapes and colours of the flowers. Their cultivation became common in Europe beginning after the 18th century and spreading widely up to the 20th century. After this period, their popularity diminished only to return with the recent introduction of new small-sized hybrids that can be grown in vases. There are numerous species and varieties. In particular, depending on their size, they can be divided into two groups: dwarf cultivars, from 20 to 60 cm high, ideal for vases and borders; and big cultivars, up to 150 cm high, with enormous heads, suitable for flower beds. To cultivate the latter, one must plant the rhizomes. The rhizomes must be planted in spring, dug out before the frost, and kept in a dry place. Big dahlias bloom from late summer to late autumn. Dwarf dahlias are less sensitive to the photoperiod and are considered seasonal plants (reproduced from seed) that bloom from June until autumn. Dahlias do not tolerate temperatures below 0°C. They thrive in well-drained, moist soils and require full sun or part-shade. They must be fed every fortnight with a 20-20-20 ternary fertilizer, especially during the first part of their growth. They are hardy plants and the treatment of parasites can be limited to combating aphids, mealybugs, whiteflies, and sometimes snails that are particularly voracious.

pianta da fiore dahlia