Grow the leopard lilies in well-draining, moist and loose soils with partial shade exposure. Loosen the soil to a depth of 6 inches and amend with 2 to 3 inches of peat moss or compost. Plant the lilies 2 to 4 inches deep in the soil. Space multiple plants 4 inches apart.
Water the leopard lily until the soil is evenly moist. Afterward, water the plant one to two times a week. The lilies bloom best when the soil is never allowed to dry out. Provide a controlled flow of water to the plant base to prevent getting splashes on the foliage.
Mulch the soil to a depth of 2 inches to reduce the rate of evaporation and keep the roots cool.
Feed leopard lilies every month during the growing season, using a 5-10-10 fertilizer diluted to half its recommended strength. Alternatively, use any fertilizer high in potash and phosphorus instead of nitrogen.
Cultivate the ground around the leopard lilies to prevent weeds from infestation the area. Although mulching reduces chances of weeds, pull out stubborn weeds by hand or use a hoe to remove them from the soil.
Sprinkle a deer repellent on the ground surrounding the leopard lilies to deter the pests. If you install a fence to stop the deer, it must be at least 5 to 6 feet tall.
Separate the leopard lilies every three to four years to prevent overcrowding. Dig around the base of the leopard lily with a garden fork to loosen the bulb before pulling it out. Twist the larger bulbs into smaller sections and carefully pull them apart. Transplant the bulbs to other parts of the yard and bury them 4 to 6 inches deep.