The calla lily is a bog plant that can become invasive if left alone in nature. The lily comes in white, yellow, pink and a purple so dark that it’s almost black. Calla lilies used to be a favourite at funerals, but they have recently become a favourite of brides. Callas are strong, versatile plants that can grow in a flower bed or become water plants on the edge of a small pond.
Find a suitable location to plant the calla lily. Since the calla lily is an early spring bloomer in USDA Hardiness Zone 8, it can thrive there under a deciduous tree. In the northern zones of 4 and 5, it blooms in late summer and should be planted in full sun. In zones 6 and 7, plant in full sun to partial shade. Callas originally came from the African marshlands and will grow on the edge of a pond if given full sun.
Add mulch and fertiliser to the soil in the fall when growing the calla lily in a flower bed. Add 5 tbsp of a 10-10-10 soluble fertiliser when working the soil in the fall to give the calla lily the nutrients and nitrogen to flower in the spring. Add bone meal for good bud development in the soil or on the water's edge.
Test the soil. The pH range for calla lilies should be 6 to 7. Add lime if the soil has too much acid and mulch and compost if it’s heavy in limestone. A county extension service or a local garden centre can also perform the soil test.
Plant the calla lily in the fall or early winter in southern zones 7 and 8. In northern zones 4 through 6, plant the lily as soon as the last frost has passed. The plants will grow in zones 9 through 11, but they prefer the cooler zones and the stems may be so weak that they won't support the blooms.
Dig a trench that's 3 to 4 inches deep with a trowel. Put the calla lily rhizomes in the trench about 4 inches apart. Cover them with soil. If you've started the plant inside, make sure the new growth isn't covered with soil.
Water the rhizomes after planting with a soaker hose. Water to a depth of 6 inches twice a week if it doesn’t rain. The calla lily will bloom in about eight weeks and will keep its bloom about four weeks. To get the full bloom time in the colder areas, start the rhizomes indoors and transplant them outside as soon as the last frost has passed. Do not fertilise in the spring or after the lily blooms.
Dig calla lily rhizomes carefully out of the soil after foliage has turned yellow. Try not to cut the rhizomes when digging. Wash the soil off with the garden hose and let dry for 24 hours for winter storage. If the lily is growing on the edge of a pond, lift the rhizome out of the water and let it dry.
Store calla lily for the winter in sphagnum peat or vermiculite in an area where the temperature is 10 to 12.8 degrees Celsius.
The calla lily can survive periods of light frost.
All parts of the calla lily are poisonous.