Are Asiatic Lilies Perennials?

Hardy Bulbs

• Asiatic lilies are hardy bulb plants. Bulbs plants are usually perennials, following an annual cycle where they sprout and flower, then die back to the ground and are dormant until the following growing season. Because nutrients are stored in bulbs, lilies can remain in the ground to sprout annually. However, some winters may be too harsh even for hardy bulbs to remain underground, undamaged, without protection.

Mulching

• To ensure that bulbs survive without damage in locations with harsh winters, provide a blanket of mulch over the plants. Asiatic lilies grow well in U.S. Department of Agriculture hardiness zones 5 to 9 without mulch. Provide mulch for lilies grown in USDA hardiness zones 3 to 4, for extra protection. Mulch also prevents bulbs from heaving out of the soil through seasonal freezing and thawing, and protects bulbs from early spring's fluctuating temperatures, preventing the appearance of shoots easily damaged by frost.The University of Minnesota Extension recommends mulching over plants before winter with 4 to 6 inches of loose, weed-free compost, leaves or wood chips.

Bulb Selection

• Choose bulbs that are firm, large, fleshy and show no signs of damage or disease. According to the University of Illinois Extension, Asiatic bulbs should be approximately 5 1/2 to 6 inches in circumference. Avoid planting bulbs that have already begun sprouting, as they will not have the energy to bloom that year.

Planting Bulbs

• Plant lily bulbs immediately after you get them, because, unlike other bulbs, they do not go totally dormant. Wait only a few days at most, but, until planting, keep the bulbs moist and store them in your refrigerator. Plant the bulbs in spring or fall in organic, well-draining soil that is slightly acidic (6.5 pH), in a location that receives sun or partial shade. Plant bulbs at a depth of three times their height, slightly higher in clay soils, handling bulbs gently as their scales break off easily. Space bulbs 6 to 10 inches apart and cover with 4 to 6 inches of soil. When shoots begin to show, fertilize lilies lightly monthly with 5-10-10. Mulching at this time, too, keeps lily roots cool, conserves moisture and prevent weeds from forming.