Oriental lilies are hybrids that were developed to be easy-to-grow, disease-resistant and to have fragrant, showy blooms. These lilies can grow to be 8 feet tall with blooms in shades of pink, red and bi-colors. There are no orange or yellow blooms in this species of lily. One of the most popular versions of the Oriental lilies is the Stargazer. These lilies are hardy to Zone 3; however, there are some growers that believe the Orientals are difficult to grow in warmer climates. Usually the problem is improper planting and care.
Choose a sunny site with soil that drains well in an area where other lower-growing plants can help to shade the roots of the Oriental lilies. In very southern climates such as zones 5 or below, plant the lilies in an area where they are protected from the hot afternoon sun. There is a popular phrase used by lily growers, which is "head in the sun, feet in the shade." Lilies love the sun, but they do not like for their roots to get hot.
Plant the Oriental lilies at least 4 to 6 inches deep. A good rule of thumb is to plant wrist deep.
Feed the lillies a time-released, balanced fertilizer that is widely available at any garden center, and follow the directions for dosage. There is no need to fertilize the lilies again until the next growing season.
Mulch the lillies with about 3 inches of mulch of your choice. This will help to keep their roots cool and allow the soil to maintain moisture.
Water deeply at least once a week during the growing season. Oriental lilies are perennials, which means they have roots that grow deeply into the ground. Set your sprinkler to water them for 20 to 30 minutes at least once a week. This will give your lilies at least 1 inch of water, which is what they need. During particularly hot and dry summers, water them like this twice a week.
Cut back in the fall after the Oriental lilies have died back completely. Do not cut or prune the lilies after the blooms are spent. Allow the leaves and stems to die back naturally. The lilies will pull nutrients down into the bulbs through these stems, where they store the nutrients for next year's growth. After the leaves and stems have died completely, usually sometime in the fall, cut them back to ground level.
Winterize the Oriental lilies by applying a layer of mulch in the fall. While the winters in warmer climates tend to be extremely mild, it is still a good idea to mulch the lilies at the end of the season. By adding a 3-inch layer of mulch, you will protect them from any possible temperature extremes. The mulch will also help to hold in the moisture.