I have a few that just wont start. They are not rotten. The temps are up. tried in pots and in the ground. Rhizomes of the same var have started already. What can I do?
keep them very warm (above 70-75) and on dry side in a good potting mix like PROMIX. Rain and cool weather will rot them.
Partially joking, put them into a plastic bag with peat moss and forget them in the back of your car for a week.
I actually did this with some Canna I purchased, only to
discover they were not only sprouting, but growing like weeds!
Putting the potted ones in a heated propagator would work.