How To…Plant Dahlias

Dahlia - Bishop of Llandaff, one of the most sought-after varieties

by Garden News |

Dahlias hail from Mexico, but are classic British cottage garden plants, and they simply thrive in our climate. Perhaps you’ve overwintered last year’s dahlia delights, so it’s time to get them out of their ‘hibernation’ now. Or you may have invested in some new exciting varieties for your collection, so get planting!

Dahlia tubers need a good amount of space to fit all their spreading parts, so dig a hole around 30cm wide and 30cm deep, and leave lots of room between each one. Plant them in a sunny, well-draining area horizontally and with a good mulch of compost at the bottom of the planting hole. You could put a stake in to start with, partly so you know where your dahlias are, and partly so they’re supported already and you don’t have to do this at a later date.

Feed your hungry dahlias through the growing season with a liquid balanced feed, but then throughout flowering a tomato feed will encourage bigger brighter blooms.

As they grow, tie them up to the stake at intervals as a sharp wind will knock them sideways. Enjoy your beautiful summer blooms!

It may be that it’s simply too cold in your area to plant out dahlias yet. They are tender when it comes to frost. If this is the case, pot them up in large enough pots to fit their bulbous tubers comfortably, with good moist multipurpose compost, and put them in the greenhouse or another frost-free place. They’ll be happy enough growing in this way until you want to plant them out at a later date.

GN Recommends

1) ‘Gallery Rembrandt’

An outstanding decorative dahlia, owing to its tightly packed fuchsia pink double petals and yellowish centres. Compact height of 40cm (16in).

2) ‘Moonfire’

A well-known vivid single dahlia with attractive deep purple foliage and fiery red and yellow blooms. Height 80cm (32in).

3) ‘Bishop of Llandaff’

One of the most sought after old semi-double dahlias from the 1920s, with scarlet red flowers and bronze foliage. Height 1.1m (43in).

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