Answer: The group of lilies called the Asiatic hybrids (Division I) are excellent hardy garden plants with the majority blooming in early summer. In general, the plant should be allowed to come up and bloom and then the spent flowers would be removed, but the stem itself would be left intact. This enables the foliage to continue to grow and help rebuild the bulb's strength for the coming year's performance. In the fall, when the stalk has been frosted or frozen and has dried, gently remove it taking care not to damage the bulb itself. If the plants are located in a spot with good drainage, they are very winter hardy and should simply be left in place with perhaps several inches of organic mulch over top of them. If you remove the stalk prematurely when it is still in active growth, it may weaken the bulb but it would not necessarily kill it.
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