Calla Lilies 101
Calla lilies (Zantedeschia sp.) are not true lilies but are clump forming plants with large arrow shaped leaves. They are used as both houseplants or seasonal outdoor bedding plants. In the garden they look great alongside ferns and hostas or near a water feature and the long lasting foliage and flowers are well suited for floral arrangements. .
Calla Lily Types
Zantedeschia hybrida are complex hybrids of different South African species and grow from deciduous tubers. They are available in a wide range of flower colors such as mango, bright butter yellow, pastel pink or true red. There is also an amazing royal purple. These plants come from mountain regions where temperatures are cool but the ground never freezes. The native light levels are high and the soil drains quickly.
Zantedeschia aethiopica has large, white blooms. The white Calla lily grows from rhizomes and hails from tropical regions of South Africa. This species prefers a very moist to semi-aquatic location and is marketed for use in water gardens as well as flower beds and containers.
The white Calla will continue to throw flowers as long as conditions are optimal while the colorful hybrids must undergo dormancy between flowerings.
Both the white Calla rhizomes and the colorful hybrid tubers prefer moist but well-draining, organic soil rich in humus, leaf mold or compost. Keep the colorful hybrids moist but avoid soggy soil situations which causes rot especially during hot weather. The white Callas are more tolerant of wet soil and once established can grow in semi-aquatic conditions.
Planting Calla Lilies
Plant your Callas after the last frost date in your area after the soil warms up a bit.
In areas with mild summers Callas grow best in full sun. Light afternoon shade is preferred in hot climates because heat stress can reduce flowering.
Plant Callas about 3 - 4 inches deep and about 12 inches apart in the garden bed or border. Even, consistent watering is important. Following directions listed on the package, apply gypsum or lime to the soil at planting to help protect the colorful hybrids from soft rot. Feed weekly until they begin to flower and then hold off. After flowering is over switch to a high potassium (the 3rd number) fertilizer. To help keep the soil temperatures cool mulch around the plants.
Watch for thrips and aphids and treat these with an organic insecticide if necessary.
Calla Lily Winter Care
White Callas (Z. aethiopica) are fairly hardy in zones 8 – 10. They may survive winter in zone 7 with a layer of protective mulch. In colder zones dig the entire plant, pot it up and grow as a houseplant over winter. In spring replant it in the garden. This is preferred to lifting and storing the rhizomes because the plants don’t go dormant.
On the other hand the colorful hybrids (Z. hybrida) need winter protection as well as a period of dormancy. Lift the tubers before the first frost and store them in trays of compost in a cool, dark, frost-free place such as a garage or shed.
Growing Calla Lilies in Containers
Callas are easy to grow in containers as long as they have consistent moisture. Use an organic, compost based potting mix. Water freely through the summer and feed with an organic, balanced liquid fertilizer every 2 weeks until the flowers have faded.
Because the colorful hybrids require a dormant period. Reduce watering to allow the plant to die back and move to a dark area once the foliage has faded. Resume regular watering in 2 – 3 months. Or lift the tuber and store in a cool and dry location between 50 and 60 degrees and replant in spring when the danger of frost has past and the soil has warmed. For earlier flowers, you can start them indoors during late winter and transplant them outside when the weather has warmed and the danger of frost is passed. To increase the number of plants you have, divide the white Callas when lifted and replanted and the colorful hybrids during their dormancy period.
Harvest flowers in the cool of the morning or evening and pull rather than cut to ensure the longest stems possible. Store the flowers at 45-48 degrees in flower preserve.
Interesting cultivars and their colors
- 'Apple Court', dwarf, white
- 'Aztec Gold', bright orange to reddish
- 'Best Gold', large and golden yellow
- 'Black Magic', yellow, throat is black
- Bridal Blush', cream with pink tones
- 'Cameo', peach, black throat
- 'Carmine Red', deep carmine
- 'Dusky Pink', light pink
- 'Harvest Moon', pale lemon yellow
- 'Lavender Petite', plum edged with blush pink
- 'Majestic Red', crimson red
- 'Maroon Dainty', plum with paler throat
- 'Crowborough', white, 4-6" long RHS award
- 'Flame', opens yellow, turns red
- 'Little Gem', white, 12-18" tall, fragrant
- 'Green Goddess', bright green, white centers RHS award
- 'Pink Persuasion', rosy pink, yellowish tints, large flowers