Rusty Hinge wrote:
I've got day lilies growing in ordinary soil - Norfolk is mainly clay on
chalk, so probably tends towards the alkaline

I'm not sure day lilies work in the same way as other lilies. I have a huge
clump of day lily that just keeps coming back no matter how mean I am to it
- every year it seems to double in size! - but I've never been able to get
other lilies growing in the same area.