How To Grow and Store Dahlia Bulbs for Heavy Flowering

Dahlia bulbs are a member of the daisy family and this Mexican plant has easily won the hearts of gardeners around the world. These, along with glads, lilies and begonia make up the most popular of the summer flowering bulbs.

And just to impress you with the botany of this plant, you will be hard pressed to find original dahlia bulbs because after nearly 200 years of selecting and hybridizing, we have hundreds of plants to choose from – but you’d have to look very hard for the original species.

Dahlia bulbs are not winter hardy and cannot tolerate frost. The first frost sees them go black very fast. Only plant outdoors in the spring after the last spring night frost. Here are more instructions on planting dahlias

Once you've grown them, you may find it useful to read about storing dahlia bulbs

dwarf dahlia

'Gallery Pablo' and indeed all shorter dahlia make excellent container plants


Aim to have the tuber (no matter how large) with a maximum of 2-inches of soil over top of it. (you can squeeze by with a touch more but not too much) Deeper plantings will reduce the flowering.

Smaller or dwarf varieties can be planted so that only 1 inch of soil is over top of the tuber.

Plant the tubers so they are roughly 12-18 inches apart for larger/taller varieties and 8-12 inches apart for shorter, dwarf varieties.

This plant wants a full sun location. The more sunshine, the better it flowers. It needs sunshine by 10 am to produce a full crop of flowers.

Get More Flowers By Doing This

To get a jump on spring, some gardeners pot up their dahlia bulbs indoors 6 weeks before they want to plant them outdoors.

Pinch off the main growing tips three weeks after you plant to increase the bushiness of the growing plant. You’ll see many more stems develop and tons more flowers. And these flowers should be deadheaded (cut off the flower and its stem) as this seems to make the tuber produce more flowers. (and we all want more flowers don’t we?)

Plant Details

  • Flower colour: nearly all colours are available
  • Flowering period: July - October
  • Planting depth to base of bulbs: 5 - 7 cm above the top of the tuber
  • Spacing between bulbs: depends on the type of dahlia (average is 5-7 per square yard or metre-squared)
  • Type of bulb: tuberous root
  • Light requirements: sunny, the more the better. Dahlia bulbs need sunshine by 10 am to produce a full crop of flowers.
  • Wintering - not frost resistant so have to be dug and stored cool and dry for the winter.

  • dwarf dahlia

    'Striped Duet

    Storing Dahlia Bulbs

    Storing dahlia bulbs successfully means following a few simple rules.

    The first is to harvest the dahlia just before or immediately after they have been frosted. If the blackened stems are allowed to rot down to the ground, then the dahlia tuber will be damaged and won’t overwinter. If the dahlia tuber is frosted, it will likely turn to mush.

    If the bulb does develop some rotting over the winter (you do check on them every few weeks don't you?) then cut the rotting area away from the tuber and dust the open cut with sulphur.

    Cool but frost-free area

    Storing this tuber is done successfully in a cool but frost- free area. A heated basement is too hot and an unheated garage where it freezes or almost freezes is similarly not a good idea.

    Remember that this is a tropical plant and getting it too cold will stop if from storing properly. Too high a heat will simply kick it into growth too early and you’ll lose it this way (if it doesn’t rot first).

    Try to keep them fairly dry as moisture will rot them. I’ve had good luck with hanging them in an old sack, burying them in dry peat moss (although they sometimes like to grow too early if buried in other growing media) and storing on a screen with air circulating around them.

    Landscaping With Dahlia bulbs

    Dahlia are long blooming plants so they combine very well in perennial borders. Their exotic looking flowers and brilliant colors act to carry the perennial border over any non-flowering periods. There’s a color and size to match almost every garden design. See below.

    Book cover spring bulbs

    Container Varieties

    The smaller dahlia bulbs are excellent container plants and do very well in mixed pots. There they bloom almost all summer requiring only weekly feeding to keep them going. Look for Mignon, Top-Mix, Dahlietta, Dahlstar, Dahlinova, and Gallery dahlias, as well as all other low-growing dahlias with compact habits to really brighten up your balcony garden or patio garden.

    dwarf dahlia

    'Impression Fantastico'

    Dahlia bulbs can be grown as potted plants and these receiving a great deal of interest; you can now grow these the same way you can buy potted chrysanthemums. You can also order these dahlias from specialty growers and do the same thing – grow them in pots for your balcony or patio.

    dwarf dahlia

    'Dark Spirit

    dwarf dahlia

    'City of Rotterdam'

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