Dahlia 'Happy Single Kiss'

Dahlias are tender perennials and the tubers can be killed by frost.

The best way is to lift the dahlias out of the ground or pot after the first frost and store them undercover. To do this, cut your dahlia plants down to 15cm before you dig them up. Knock off the surplus soil and, with a small piece of stick, scoop out the loose soil between the tubers – but leave enough to hold them in place.

Do not clean your lifted tubers under a tap; to get water on a tuber at this time of year often spells disaster. Turn the tubers upside down in a crate and leave to dry for a couple of weeks, then pack them in shallow trays or boxes either in very dry compost or wrapped in newspaper before placing them somewhere cool and frost-free.

A common mistake is to regularly water tubers you have just planted and too much water at this early stage can lead to rot. Water the compost once when you first plant the tuber, then wait until you spot the first sprouts before watering again.

Underwatering your dahlias is the most common reason for failed blooms. Keep the soil moist and water generously, especially in a drought or if you’re growing them in pots. Make sure they are positioned in full sun, ideally in a sheltered place.

There are a host of options when it comes to protecting dahlias from slugs. Try nematodes, a biological treatment you water onto your garden in early spring then repeat periodically, or harmless slug-repellents such as wool pellets, which form a natural barrier to slugs and snails. At Perch Hill we’ve created a garden that’s a haven for birds, and birds have helped to reduce the number of slugs by eating them.