Here are a few important tips on how to care for tropical bulbs from The Old Farmer's Almanac.
When buying tropical bulbs, look for tubers with three to five eyes and initial root formation. In general, look for firm and healthy bulbs. Bulbs that are mushy usually have not been kept in a cool, dry place and will rot and therefore not flower.
Summer-flowering bulbs and tubers can be planted in the spring when you are certain that the ground will no longer freeze in your area. This may be up until the end of May, depending on your area. The bulbs need sufficient water and humid conditions.
The rule of thumb is to plant the bulb or tuber about 5 inches deep—except for dahlias and begonias, which should be planted just beneath the surface.
Once your summer bulbs have finished blooming, they can often be used again the following year. With the exception of lilies, the bulbs have to be taken out of the ground if it freezes in your area during the winter. If it does freeze in your area, let the leaves die down naturally, and then dig up the bulbs and store in a cool dry place to replant the following spring.
For more information about summer bulbs, see our Spring-Planted Bulbs chart.
For care of other bulbs, see our Fall-Planted Bulbs chart.