Dark Maroon-Purple Blooms. If you haven't grown callas, you may be surprised that these bulbs create a sizable plant. Sometimes the clumps grow 36" high. Most all callas have pointed or heart-shaped foliage that's dark green spattered with white spots. The bulbs are irregular, sort of like ginger roots, and several can be planted in the same pot. They enjoy being root-bound. If you plant your bulbs in spring, you'll have flowers in about 65 days.