Calla lilies are a favorite flower for wedding bouquets and elegant cut arrangements. Even the Latin genus, Zantedeschia, has an elegant sound (pronounced zan-teh-DESK-ee-uh). They are widely available from florists, but a little pricey. How fortunate for gardeners, then, that they are so easy to grow.
Known as Calla lilies, these are not really a lily. Instead, they are a long-lasting South African bulb (rhizome) in the same family as Jack-in-the-Pulpit. Most internet sources and pre-packaged bulbs indicate that the bulbs should be planted 4 inches deep. In the southeast’s heavy clay soil, they want to be planted very shallowly, with the top of the bulb exposed. It can be challenging to determine which side is “up” so look carefully for the growing points. You can plant them outside after the soil is warm, or you can start them indoors if you are looking for a head start. They sulk in cool soil. For most bulbs, size matters – the bigger the bulb, the bigger the plant. In the case of Callas, size is not as important as the number of growing points or eyes. A large bulb with a single grow point will not produce as well as a much smaller bulb that have several points.
Callas prefer average to moist soils with plenty of organic matter but will not survive in a bog. They must have sun to bloom well, but full sun tends to scorch them a bit, so locate them in a partly shaded area. Ideal placement has morning sun, afternoon shade. Provide supplemental irrigation when rain is limited. Plants reach 20 to 30 inches tall. Even when not in bloom, Calla foliage is attractive, almost like an Arum. In the UK, the common name is Arum Lily. Many Callas have white freckles on their leaves. In my zone 7 garden, the leaves remain attractive until late fall. Don’t remove the foliage until it yellows.
Callas are often received as a gift potted plant, then discarded once the blooms fade. Please give them an opportunity to beautify your garden beds. (They do well in containers, too.) My favorite specimens came from a local grocery store. The plants had passed their prime, had been ignored by the staff (no watering), and looked dreadful. I allowed them to remain in their containers while they spent the winter in a cool garage with just a little water. In spring, I planted them outside in rich soil, morning sun, and plenty of water. They repaid my love with numerous flowers. These last a long time in the vase. Calla blooms are a spadix (a spike of tiny flowers) located in the throat of a spathe (a large bract or sheath). While white is the most common color, Callas come in an array of shades: yellow, apricot, pink, purple, deep red, and almost-black.
Callas are listed as cold hardy in zones 7 to 10. If you are cooler than zone 8, provide a deep but light-weight mulch like pine needles or grow them as annuals or houseplants.
Deer and rabbits usually leave Callas alone. The bulbs are highly toxic and may be fatal to humans and pets if eaten. Keep this in mind if you have indoor pets and plan to grow them as houseplants.
I divided and moved these two colors last August, at the worst possible time of the year. Yet, they survived and even bloomed in their new location.