Dahlias: types, meaning and summer care

Where dahlias come from

Dahlias are tuberous perennials from Mexico and Central America, and the dahlia is Mexico’s national flower. Swedish botanist Anders Dahl gave the genus its name in 1791. Gardeners have since bred thousands of cultivars, covering every colour except true blue.

The shapes to know

• Dinner plate: huge, ruffled heads that can fill a whole vase on their own.
• Pompon and ball: tight, perfectly round globes that last well and pack neatly into bunches.
• Cactus and semi-cactus: spiky, rolled petals that look almost like fireworks.
• Waterlily: shallow, flat-faced blooms with layered petals.
• Single and anemone-flowered: one ring of petals around an open centre, loved by bees.
• ‘Café au Lait’: a creamy blush-apricot dinner plate, a favourite for wedding flowers.

What a dahlia means

Dahlias have no single fixed meaning, but they are usually read as a sign of confidence, creativity and commitment, and gifts of dahlias often say you are remarkable. A warm yellow or apricot bunch suits a thank-you, while deep burgundy feels dramatic and celebratory. For the longer list, see our guide to flower language.

Cut dahlias in a hot country

• Choose blooms that are already open. Unlike a rose or tulip, a tight dahlia bud rarely opens once it has been cut.
• Give stems a fresh, sharp cut, strip the leaves below the waterline and use cool water.
• Dahlias are thirsty, so top the vase up every day and replace the water completely every second day.
• Keep the bunch out of the afternoon sun, away from the fruit bowl and well clear of the air-conditioner.

A bunch that looks tired by the fourth or fifth day is quite normal, since dahlias are one of the shorter-lived cut flowers. Our care tips cover general routines, and you can order flowers with dahlias whenever they are in season.

Growing them in the garden

In Melbourne, Canberra, Hobart and the highlands, plant tubers about 10 cm deep in spring with the growing eye facing up. They want six hours of sun and well-drained soil, and the plants will bloom for longer if you pick them often. In frost-prone places lift the tubers after the first hard frost; in Sydney and Brisbane they usually stay put, though humid weather brings mildew. Slugs, snails and earwigs love young shoots, so protect them early.