After the lively Asiatics have faded and before the tiger lilies bloom, the Oriental lily rules the late summer garden. As with any true lily, pruning Oriental lilies is a simple but strictly timed process of annual maintenance. These popular perennials grow from bulbs, highly developed roots that hold a year's nutrients for the following season's blooms. As the storage organ of the lily plant, the bulb gathers food generated by the green parts of the plant long after its flowers have faded.
Strip pollen if you wish a longer bloom from your lilies. Simply pull the brown or black pollen from the anthers and into a paper sack. Use this strategy to keep flowers you cut for indoors fresher longer, too.
Deadhead blooms as they fade. Snip the flower off at its base with a scissors or your fingers.
Cut flowers or trim flower stems back when the leaves start to wither. Cut no more than a third of the stalk so that enough leaves are left to produce next year's blooms.
Trimmed the stalks back as they wilt, providing the leaves are completely dry before that part of the stalk is trimmed back. Oriental lilies, which can grow as tall as 6 feet, can afford to lose dead growth to look neat.
Allow the lily stalks to dry completely before pruning the stalk all the way down to the soil surface. The stalk should be dry enough to pull loose from the bulb.