What is the best time to buy / plant tree lilies? I have seen several conflicting articles.
I also read that planting them over a layer of gravel helps with the drainage - anybody any experience of this?
They do like decent drainage, all Lilly's do. Bulbs are usually planted early spring and flower first year. If you have decently drained soil they'll over winter quote happily in situ. Decent drainage through is key to survival in soil or pots.