My dahlia Moonfire is shooting particularly early this year. I do not want to do root cuttings again and do not have the space to put them in more light. What is best for the rhizomes – cut off the shoots or let them grow?
Dahlias sprout in soil temperatures of 12 degrees celsius and up, so should be stored at 10 degrees celsius or less over winter- too late for this year, but should help next winter. This year you are about 7 weeks away from ideal spring planting temperatures, without the risk of damaging frosts.
The shoots on your tubers should be trimmed (if it was closer to planting time they could be left to grow) so that they don’t use up too much of the energy stored in the tubers. Each tuber has a finite source of available nutrients. The nutrients help them survive winter and dry months as well as allowing the plant to regrow each spring. By removing the shoots now you are preserving the store of nutrients that will be in demand in May when you plant your Dahlia ‘Moonfire’ into the garden.