I have ten LA's that I wanted to grow close but I wanted to keep them from intermingling if I could. I planted each one in a plastic pot. I used a very large old zinc wash tub and made drainage holes in the side of the tub about three or four inches from the bottom with a nail. Then I filled the tub with garden soil until it was level with the bottom of the pots. I cut the bottoms of the pots out and sat the pots on the soil. I filled around each pot with the same soil until it is almost level with the tops of the pots. The thinking behind this was that the roots could go all the way down freely while the side of the individual pots would keep them from intermingling. The irises are thriving there as the very bottom of the tub will hold water a bit longer than the soil in the top of the tub. Whether or not they stay put is something I will just have to see in the future.
