In spite of their exotic beauty, Asiatic lilies are tough, durable and so easy that even a beginning gardener will be able to grow them like a pro. Asiatic lilies are available in a variety of sizes, and in combinations of all colors with the exception of blue. To keep Asiatic lilies looking their best, divide them every two to three years. The best time to divide Asiatic lilies is in early autumn, after the foliage has wilted and turned yellow.
Prepare a spot in advance so you will be able to plant the divided Asiatic lilies before the roots dry out. Plant Asiatic lilies where they will get plenty of morning sun, but will be protected from hot afternoon heat. Use a garden fork or a shovel to cultivate the ground to a depth of 10 to 12 inches, and remove any large stones or dirt clods.
Use a straightedge shovel or a garden fork to dig a clump of Asiatic lilies for division. Insert the tool straight down into the ground 8 to 10 inches from the clump, and rock the tool back and forth gently to loosen the roots. Dig around the perimeter of the clump, then lift the Asiatic lily bulbs out of the soil. Be careful not to dig too close to the clump because you risk slicing into the bulbs.
Spray the Asiatic lily bulbs with a garden hose to remove excess soil, then divide the bulbs by carefully pulling and twisting them apart. Discard the old, woody clump of bulbs at the center of the plant and save the small bulbs for replanting. Be sure each small bulb has several visible roots.
Plant the small Asiatic lily bulbs in the prepared location. Asiatic lily bulbs should be planted to a depth of about three times the height of the bulbs.
Water the Asiatic lily bulbs after planting, and keep the soil damp until you see new growth emerge, which should take just a few weeks. After that time, Asiatic lilies need very little water.
Spread an inch of organic mulch such as bark chips around the Asiatic lilies, and replenish the mulch every spring. Be sure to spread the mulch around the lilies and not directly on top of them.
Deadhead Asiatic lilies by removing spent blooms as soon as they fade. You can also cut Asiatic lily blooms to use in cut flower bouquets. For a long-lasting bouquet, trim one-half inch off the bottom of the stalks, and add fresh water to the vase every day.
Leave the stems and foliage in place after the Asiatic lilies are done blooming. Wait until autumn to remove the foliage, after it wilts and turns yellow. The green foliage provides energy to the Asiatic lily bulbs, which they will store for the next year's blooms.