Clear weeds from a location with sun in the morning and afternoon but shelter in the heat of the day. Partial sunny locations yield the largest and most spectacular flowers. The rhizomes can be planted near a pond, in a ditch or in any overly wet area.
Dig a trench 6 to 8 inches deep. Add 2 inches of compost and work it into the soil. The compost will provide nutrients and increase water retention. Place the dwarf calla rhizomes in the soil at least 4 inches deep and 1 foot apart. Fill in the trench with soil and press it down around the rhizomes.
Mix granular fertilizer into the top 2 inches of soil after planting. Use the amount recommended by the manufacturer for the total area planted. Water the area until the water pools at the surface of the soil. Consistently keep the rhizomes moist. Dig a little trench 6 inches down near the plants to check for dampness.
Cut back the foliage to 2 to 4 inches from the ground, after it has died back. Mulch around the plants in fall with steer or other manure. Spread 2 inches of mulch to add nutrients and protect the plants. Fertilize again in early spring.
Plant rhizomes in pots or in up to 4 inches of water at the edge of a pond. Calla lilies can be sown in large masses or in smaller clumps of three or four. The dwarf calla lilies are small and need to be near the front of the garden bed to be seen.