The Dahlia is a member of the aster or sunflower family (Asteraceae or Compositae) and is originally from Mexico. There the dahlias were grown for their edible, oblong, tuberous roots. These tuberous roots where boiled and eaten as vegetables. They taste like artichoke. Also the hollow stems of the Dahlia imperialis where used as water pipes.
The leaves can vary from species to species. Almost all cultivated dahlias are hybrids.

The most common cultivar groups are:

  • Single (rich in nectar)
  • anemone
  • collerette
  • waterlily
  • decorative
  • pompom
  • cactus
  • semi cactus
  • and various smaller groups

Dahlias are not very hardy, but if your winters are as mild as mine you can take the gamble and leave them in the ground. Here it does not get much colder than about -10 ºC (14 ºF) for a short period nowadays. Since 2017 I leave the tuberous roots of the Dahlia ‘Gallery Singer’ in the ground during the winter and it has not died yet. The dahlia emerges in spring and blooms from July till October.

You can also dig up the tuberous roots just before frost sets in. Cut the stems to about 15 cm (6 inches) from the tuberous roots and store them in a dark, dry spot. You can roll them in some paper for example. Definitely do not put them in plastic because the tuberous roots will rot then. In February/March you can start the dahlias into growth indoors. You put the tuberous roots in a pot and place that in a warm environment (minimum 17 ºC (63 ºF)) in the light and keep the soil moist. If you are sure that the frosty days are over, you can plant them in their flowering site.

Plant the tuberous roots about 10 cm (4 inches) deep and about 40 cm (16 inches) apart. The bigger the dahlias grow, the further apart the tuberous roots should be planted. Dahlias that grow up to 60 cm (24 inches) or higher may need some support to prevent them tumbling over with strong winds or rain or their own weight.

New growth in spring is a feast for snails and slugs so you have to stay on guard as long as the dahlia is still small. Earwigs can disfigure the blooms.

When the plant has developed a full third set of leaves, you can pinch out the center. This will produce a bushier plant with more blooms. Deadheading stimulates reflowering. Dahlias make excellent cut flowers and by cutting flowers for you bouquet, you stimulate the production of new flowers.

They prefer well-drained, humus-rich soil and a sunny spot with shelter against strong winds. Dahlias are somewhat deer resistant. It might not be the first plant or flower they will eat, but they may eat them.



Attracts bees: no

Characteristic: newly emerging every year

Exposure: sun/ part shade

Deer resistant: no

Flower color: red

Flowering time: July – October

Foliage color: green

Fragrant flower: no

Hardiness: -10 ºC (14 ºF)

Height: 16 inches (40 cm)

Soil: normal/ moist