A Mexican flower with a Swedish name
The Spanish botanist Cavanilles named the genus in 1791 in honour of Anders Dahl. Around 49 wild species are known, all in the daisy family, and the dahlia was declared Mexico's national flower in 1963. Gardeners have bred thousands of cultivars since, in nearly every colour except true blue, from 5cm buttons to dinner-plate heads of 30cm.
Fitting a dahlia to Irish weather
Our mild, damp Atlantic climate suits the plant in one respect and not in another. Summers rarely scorch the foliage, so flowering runs on from July deep into autumn. On the other hand, wet ground rots tubers, and slugs and snails go for the new shoots in spring.
- Plant in free-draining soil in full sun, adding grit on heavy ground.
- Start tubers in pots under cover and plant out once frost risk has passed.
- Pinch out the shoot tip at about 40cm to get a bushier plant.
- Deadhead often, because the plant keeps producing buds as long as seed heads are removed.
Lifting or leaving?
The Royal Horticultural Society notes that in milder parts of these islands tubers may survive winter outdoors under a thick mulch. Near the coast that is a fair gamble; in an inland frost pocket, lift them after the foliage blackens, let them dry and store them somewhere frost-free.
Pets
The ASPCA lists dahlias as toxic to dogs, cats and horses, with mild stomach upset and mild skin irritation as the signs. Ask your vet if an animal has chewed the plant.
