Dahlias are very sensitive to frost. In winter, they must be protected from sub-zero temperatures. Ideally, the tubers are dug up and stored indoors. In sheltered locations and very mild winters, hibernation can also be successful outside.
Overwintering dahlias outside is very risky
Winterizing dahlias outside
- Cut down georgines
- Build up a thick layer of soil and foliage
- Secure with bubble wrap
The problem is that you don't know beforehand whether the winter will be very cold. An attempt to overwinter dahlias outside is therefore only worthwhile if the planting site is in a sheltered place.
Wetness can also be fatal to the tubers. If the winter is very humid, the moisture cannot escape through the thick covering. This causes the roots to rot.
tips and tricks
In addition to frost and too much moisture, voles are a threat to dahlia bulbs that overwinter outside. They eat up the tubers, so next spring you wait in vain for new shoots.