Both are easy, just plant in your garden when the ground warms up, the end of June, in moist soil. Caladiums are valued for their foliage - being decorative, not their blooms, which are obscure and better snipped off, to encourage more leaves. Plant them in mostly shade. Dig up in fall before hard frost, dry bulbs for a few days, clean dirt off, store in a box at 70 degrees. You can grow them the following year if they are successfully stored over winter.

I only grew Callas once, I don't recall that the bloom time was very long, less than a week, but someone else may have better experience to share.

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never tried the callas, but I get the caladiums every year in the spring, to dress up some shady nooks. they can be lifted and stored like dahlias in the fall, by the way - I'm just lazy ;)

what I've also found is that my local farmer's market stocks a number of tropical tubers - so, every year, I pick up a half-pound of 'eddo' tubers for under a buck, and plant them about 8" deep, and water them heavily...and am graced with the green 'elephant ear' taro plants they sell for $8 a bulb in the garden stores :)