How to prune formosa lily

Deadhead as flowers fade (late summer to early autumn); cut to ground after frost or foliage yellows. Remove spent flower heads at their stem junction. Allow foliage to die back fully, then cut the whole stem to soil level. Collect seed only if intentional propagation is desired.

Annually — deadhead to control spread, autumn cut-back after senescence. Formosa lily blooms late and can self-seed prolifically; deadheading spent flowers promptly reduces unwanted spread. Leave all green stems and leaves to feed the bulb until they yellow naturally in autumn or after first frost. Cut to ground level then. In mild climates it may behave as a short-lived perennial — rejuvenate from seed or offsets.

Remove spent flower heads at their stem junction. Allow foliage to die back fully, then cut the whole stem to soil level. Collect seed only if intentional propagation is desired.