Traditionally the time to lift Dahlia tubers is after the foliage has been frosted, but before it gets so cold that the tuber itself is affected. Dahlias are tender herbaceous perennials that can be lifted and stored. They have fleshy tubers that can survive in a dormant state when lifted and stored.
How to do it
- Using secateurs, cut down dahlia stems to a few centimetres from ground level and compost the leaves.
- Lifting dahlia tubers with a fork – Dig all around the dahlia clump and lift the tubers with a fork, taking great care not to damage them with the spikes. Shake off as much soil as you can.
- Rinse off the soil, then stand the tubers upside down to dry.
- Pack the tubers in a box or pot and cover them with dry compost.
- Store them in a frost-free place, such as under the greenhouse staging or a dry shed.
In milder areas of the UK and in sheltered, well-drained, parts of the garden, it may be possible to cut back the tops, leave them in the ground and cover them with a thick mulch to protect them over winter. In very cold or exposed areas, even hardy perennials may need the protection of mulch over winter.