When to Plant Calla Lillies?

Growth Characteristics

• Although subtropical in origin, calla lilies die back in winter or drought but remain alive in their underground rhizomes. Since the plant remains alive in the rhizome, it may be planted any time of year as long as it will not be killed by dry soil or subfreezing underground temperatures. When the soil is moist, fertile and warm, the rhizome sprouts leaves, stems and eventually flowers through spring and summer.

Hardiness Considerations

• Calla lilies overwinter outdoors in the soil in regions with cool to mild winter climates. In U.S. Department of Agriculture plant hardiness zones 8 through 10, the rhizomes or potted plants may be planted year round but usually best planted in spring since growth quickly follows planting. Elsewhere, calla lily rhizomes or container-raised plants are planted in spring when the threat of spring frost ends and the soil is at least 50 degrees Fahrenheit. In USDA zones 7 and colder, the plants grow in the ground to flower up until they are killed back by fall's first freeze. Then, rhizomes are dug up and brought indoors to escape winter in a cool, moist container filled with sawdust or sphagnum at a temperature between 45 and 60 degrees.

Planting Location

• For best growth and abundant flower production, plant calla lily rhizomes in a partial sun location with five to eight hours of sun rays daily. Fertile sandy loam soil needs abundant organic matter like manure and compost added to sustain the plants. Overall, keep the soil on the moist to wet side. The more sunlight a calla lily receives, the wetter the soil required. Too little soil moisture weakens leaf growth and inhibits flowering, as does planting calla lily in too dim of light exposure. Calla lilies may also be grown in containers that are partially submerged in a shallow freshwater pond in full sun.

Planting Tips

• Follow specific planting requirements listed on literature that accompanies purchased calla lily rhizomes. Otherwise, the general planting guideline is to dig a hole 4 to 6 inches deep. Place the rhizome horizontally in the planting hole, orienting the pointed buds upward. Buds sprout and reach the soil surface more quickly if soil is warm and evenly moist. Once leaves appear from the soil, increase watering and apply fertilizer to coax lush growth and subsequent flowering.