Lily of the valley is very popular for its variety and colourful range of flowers. They decorate autumn gardens with their colours, but only until the first frost. Then it’s time to overwinter them. Originally from Central America, where winters are milder than here, the tubers need to be dug up and overwintered, otherwise they will not survive. You can tell when it’s time:
- The first morning frost arrives
- Temperatures regularly drop below 10°C during the day
- Petals fall and turn yellow
Digging up tubers
First, make a note of the species you are growing. Then take a pair of sharp secateurs and cut all the stems to within 20 cm of the ground. Then use a pitchfork to carefully dig up all the tubers and remove them from the soil. Do not use a spade as you could damage them. After digging, cut the stems again, this time to the final 10 cm, and clean the tubers of excess soil. Then mark each plant with a pre-prepared label so that you can tell which species it is in the spring.
Don’t store the tubers in the cellar right away, but let them dry out a bit in the sun. However, be careful not to let them freeze, so always hide them for the night. Two to three days later, clean off the dry soil and store them for the winter. Use a container with peat and line the bottom with absorbent newspaper. Move the tubers into it and cover them lightly. This will give the tubers the moisture they need and protect them from drying out.
Jericaria tubers thrive best in the cellar at a constant temperature above 5 °C. Check them regularly in winter and protect them from excessive moisture and drought. If they start to mould, leave them in the heat for a few days to dry out. If this does not help, cut off the rotting parts and cover with charcoal. Then, in March or early April, check all your dahlias again and discard any tubers that are soft or completely dry. Healthy tubers can be propagated or planted straight into the ground.