I have several mounds of these geraniums and I want to transplant them. Is fall a good time for this perennial? I know many fall is a good time for transplanting most plants.
Dory, there is no better time to transplant than NOW.
When the plants are in dormancy, they are not required to put energy into producing leaves and just like trees, will put more emphasis on setting roots.
To that, when you dig the hole, do mix in some good organic material to hold moisture and add in some transplant fertilizer...something like 10/52/10.....or triple superphosphate...0/46/0...and water it in well.