Dahlias are right back in vogue this season, thanks to their sumptuous billowing blooms in a kaleidoscope of in-your-face colours. The free-flowering stems are fuelled by a collection of fleshy, finger-like tubers, which are traditionally lifted each autumn to protect from harsh winter frosts. If you live in a mild, coastal site with free-draining soil you might get away with leaving them in the soil year-round, but for the rest of us, how do we go about lifting and storing them this month?
Once the first frosts hit, generally in November, your dahlia foliage will become blackened. Cut this down to just above ground level using loppers or stout secateurs.
The next step is to gently tease the tubers out of the soil. Lift them using a garden fork, inserting it well away from the clump so as not to pierce and damage the tubers.
Carefully wash off excess soil from the tubers as this can harbour damaging pests and diseases. Dunk the roots in a bucket of water or push it off using a jet of water from a hose.
Dust the roots with antifungal sulphur powder, and then lay them untouching in a tray. Pack them with compost and keep them dry and frost-free till the spring.