Calla lilies (Zantedeschia spp.) grow 30 inches tall and spread 24 inches wide. These summer bulbs produce waxy flowers in bright or pastel shades of white, red, yellow, pink and purple. Speckled green leaves grow under the goblet-shaped flowers. Calla lilies give can give your garden a tropical look. Try planting these elegant flowers in containers, flowerbeds, borders and around waterways. Calla lilies are often used as cut flowers, which can last for two weeks in a large vase of fresh water. Calla lilies are a low-maintenance flower to grow.
Remove the weeds and grass from the planting site after all danger of spring frost is past. Choose an area with afternoon shade and moist soil. Mix 3 inches to 4 inches of compost into the top 8 inches of soil with a shovel. Plant the calla lily bulbs so the tops of the bulbs are 2 inches from the surface and 12 inches to 24 inches apart.
Sprinkle the planting area with water until the moisture reaches the depth of the bulbs. Calla lilies like wet soil, so water whenever the soil starts to dry out. The goal is to keep the top 2 inches to 4 inches wet.
Spread a 1-inch layer of mulch such as wood chips over the planting area. Mulch prevents quick evaporation of moisture from the soil. As the calla lilies grow, refresh the layer of mulch to keep it at the 1-inch depth.
Broadcast 20-20-20 slow-release fertiliser over the area after planting. Water the area right away to activate the fertiliser. Use half-strength water-soluble balanced fertiliser every two weeks while the calla lily is actively growing. Stop feeding the calla lilies when the flowers start to die.
Remove the fading flowers by cutting the stems with a sharp knife. This keeps the flowerbed tidy and neat. Wet weather can cause leaf spot fungus to damage the leaves. Remove the injured leaves in order to control the fungus.
Calla lily bulbs are frost-tender and suffer damage when temperatures fall below -3.89 degrees Celsius. In warm climates with mild winters, leave the bulbs in the ground. Otherwise, dig up the calla lily bulbs right after a hard frost in the fall and store them in dry peat moss. Keep the bulbs at 10 degrees C to 15.6 degrees Celsius.
All parts of the calla lily plant are poisonous. The high level of oxalic acid in the calla lilies causes burning and swelling of the tongue, mouth, throat and eyes; nausea; vomiting; and diarrhoea. Calla lilies are deadly to livestock, pets and children.