I have several of the so-called tree lilies. A few of these varieties are also available from normal lily nurseries, where they are simply described as normal lilies.
But it is true that they are very tall, and very impressive. A have three varieties which are well over 7 feet. The only major problem is that the massive flower heads become very heavy after rain, and may cause the stems to bend over quite worryingly. Although the stems are quite strong, I do attempt to stake mine.
This one is Manisa, from T&M. It's left outside during the Winter. I give an occasional feed of tomato feed, when I think if it. The only regular maintenance that you really must do is to check for lily beetle, every few days. Just 3 bulbs here....