Q.Transplanting Oriental/Asiatic Lilies
Is it safe to transplant Oriental/Asiatic lily trees the beginning of September in Zone 5a?
Certified GKH Gardening Expert
It is best to leave the lily in place as long as it has green leaves, so that they can photosynthesize and store energy in the bulb for the following season. When the leaves die back, then you can dig up the bulb to transplant. This might be in September or later than September but before your first frost. These articles will help:
https://www.gardeningknowhow.com/ornamental/bulbs/lily/growing-tree-lily-bulbs.htm
https://www.gardeningknowhow.com/ornamental/bulbs/lily/dividing-lily-plants.htm
https://www.gardeningknowhow.com/ornamental/bulbs/lily/dividing-lily-plants.htm