Some dahlia stems were broken off and I have trimmed to just below a leaf joint and stuck in jar of water wondering of they will eventually show those little 'rootlets'at base of stem if I leave them long enough and can then be grown on over winter. Does anyone have any idea please?
If they have hollow stems, then no.
If not, it is possible they may root, but would need to be kept warm over winter.
When you don't even know who's in the team
You'll notice that they will recover quickly. I would be patient. Divide your tubers next spring to increase numbers .Rather than going down the road you've decided to go.
Thanks both. Yes you are right they do have hollow stems, so will go back to cuttings next spring.