Donald,
The Scarlet O'Hara for some reason seems to send up more blooms than the other varieties. Why, I don't know.
Caladiums love bone meal and as far as fertilizer goes just use a 6-6-6 blend and they'll do fine. Caladiums are NOT heavy feeders!!
I would be careful using a fertilizer that has a lot of nitrogen in it. Nitrogen CAN affect the coloring, especially the white varieties!!
Bill
