Proper watering is the single most important aspect of caring for calla lily plants. The calla lily (Zantedeschia aethiopica) is a perennial herb native to Africa, also known as Lily of the Nile, Easter lily and Arum lily. Calla lilies are bog plants and prefer moist sunny locations like riverbanks and swamp edges, and soggy soil to dry. From the beginning of the plant's life cycle to the end, correct watering care is integral to calla lily survival.
Calla lilies grow from a bulblike root called a rhizome. Lily rhizomes need to be watered immediately after planting in the spring. If planted in the garden, the lily rhizomes must be watered until the ground is saturated. If planted in a pot, the calla lily needs to be watered until the soil is moist and water drains freely out of the bottom of the pot.
Calla lilies need to be watered thoroughly as soon as the first signs of new growth emerge from the rhizome. Within a few weeks of the first early growth, long shoots develop; these shoots eventually become the calla flowers, which are actually modified leaves called "spathes."
Outdoor calla lilies require frequent watering during the growing season, which runs from early spring to summer. The soil must always be kept moist to ensure proper growth and development. Water at the base of the plant, once a week or more, depending on the soil's condition.
Indoor potted calla lilies need even more frequent watering. Potted calla lilies need a drink once a day. Water at the surface of the soil, saturating the growing medium until the water drains out of the bottom of the pot. Peat moss and a compost-rich potting soil assist in water retention and conservation.
Conserve Soil Moisture
Conserve soil moisture to aid in successfully maintaining calla lilies. In the garden, a layer of compost or mulch works well to preserve moisture. The potted callas should be placed in a spot where the pot is in the shade but the leaves and flowers receive full sun. This helps to prevent moisture evaporation from the pot.
After blooming has ceased and the foliage has gone dormant, callas are watered for one last time. Water the soil of outdoor calla lilies well. For potted callas, water until the excess drains from the bottom of the pot. If the calla rhizomes are to be stored indoors for the winter, there is no need to water.