Hello David and welcome to the forum. May I ask please. Why do you consider it unwise to plant lilies in pots ?
I grow lots of lilies, being a member of the RHS Lily Group. In line with members comments. Growing or attempting to grow from seed, can be a lengthy process and so often disappointing. Growing species lilies, due to their often rarity, it is beneficial to use pots.
To mix & match, pot culture can produce some great displays. Lilies generally like a well draind site, often a woodland site is just the job and they can be left to establish. For growers with limited space, pot culture will allow the pots to be stored once flowering is over.
Please continue to enjoy your lilies.. I wish you well.