Grown for their beautiful, exotic flowers, tiger lilies (Lilium columbianum), also known as Columbia and Oregon lilies, produce orange bell-shaped blossoms adorned with dark spots. Native to the West Coast, these flowers dangle from 5- or 6-foot flower stalks each summer in U.S. Department of Agriculture plant hardiness zones 5 through 9. Tiger lilies make excellent border plants, and are often planted along fences or driveways. Tiger lilies grow from bulbs, which are best planted in fall or early spring.
Turn the soil 12 inches deep with a spade, creating a bed along the fence or border that is at least 12 inches wide. This space accommodates one row of plants. For every additional 6 to 12 inches of width, one more row of lilies can be planted. Incorporate 3 or 4 inches of organic matter, such as compost, into the turned soil to create a well-draining, organic medium. If the fence slats are closely spaced and let little to no light through, perform these tasks on the south, west or east sides so the lilies receive partial shade to full sunlight; the north side will likely be too shady.
Plant tiger lily bulbs so the tips are 4 to 6 inches below the soil surface, starting the first row 6 inches from the fence or edge of the border. Space bulbs 6 to 12 inches apart, staggering rows for a more attractive space. Spread a 2- or 3-inch layer of mulch on top of the tiger lily bed to conserve soil moisture.
Water the area with 1 inch of water at planting time and when the soil feels dry 2 inches deep. Irrigate in the morning so the foliage and ground can dry out during the day, reducing the risk of fungal diseases.
Snap the flower heads off the stalks with your fingers after they fade to direct the lilies' energy to creating more flowers, rather than seed production. Sterilize pruning shears with rubbing alcohol and cut the foliage to the ground after it turns brown. Discard the trimmings to prevent fungal diseases from forming.
Irrigate tiger lilies with less frequency during fall and winter, watering only during drought-like conditions. Otherwise, the bulbs could rot. Return to watering when the soil is dry 2 inches deep in spring after the last frost.
Dig around lily clumps as they emerge in spring, going about 8 to 10 inches deep to ensure you clear the bulbs. Separate the bulbs with your hands, and replant them in the same manner as you did when they were first planted. Divide tiger lilies every three or four years when the bed becomes overcrowded and the flowers produce fewer blooms than previous years. Thinning out the planting also helps prevent fungal diseases.
Spray the foliage and ground with a fungicide if it becomes inflected with botrytis blight, a common issue with lilies. Botrytis blight is noted for its reddish-brown spots. Repeat this treatment each spring when the foliage emerges from the ground as a preventative measure. Also, spray aphids, another common problem with lilies, with a stream of water from your hose to control mild infestations. Spray the undersides of the foliage and stems until they are wet with an insecticidal oil to control larger infestations.