Please see if you can answer the "Help with caladium growth habits" question!
Caladiums may not show vigorous growth until the soil temperatures warm to thier liking, for a significant amount of time during each day. Consider the area they are planted; if the soil is in full shade it may not be warm enough for optimum growth as of yet. Here in the Dallas area, the soil has been warm enough for maybe the last month. We can try to plant them early, but the cooler temps will still retard the growth, and if it rains before they begin to grow, the tuber may become to moist and rot. Soil temps above 70 F are generally safe to plant. Their tropical origins can be difficult to replicate sometimes.
I have had some luck by wetting the bulbs with luke warm water, then letting them dry, for about 3 weeks prior to planting. I do this once on the first week, then twice the second week, and then evey other day for 4 to 6 days. This needs to be timed for the end to occur when the bulbs can be planted in a warm soil. If outside conditions are still too cool, they need to be planted in peat pots. This technique seems to spur the bulbs to life and cuts 7 to 10 days off the early development time.