I'm not sure why Karen North likes me. Despite two seasons of early cold damage, an accidental dowsing with triclopyr (a broadleaf weedkiller), and twice testing with a spray of Liquid iron* that it wasn't appreciative of, it's 5.5ft tall now. It grows in a clay base soil, amended with sand and compost eight years ago, and that soil still cracks severely in the dry season. I only have maple and ash leaves (quickly decomposing) for mulch, so I don't have a good layer all summer long. But it does get high thin shade from an Amur maackia (tree) in the afternoon from around 1pm on. Like any lily with strong lineage from mountain environments, one key is probably keeping the soil as cool as possible.
* Liquid Iron is a product containing iron, magnesium, manganese, copper and zinc. I use it to help combat chlorosis in early stage growth of my martagon section lilies.