Thanks, Bob ...
It's not water retention really that is the major problem. I can manage that. It's low humidity that leads to leaf scorch. The plants simply cannot pull enough moisture up into the leaves to hydrate them so they are more susceptible to the heat.
I went out and checked the mature heucheras I have planted in the garden and we are in our second day of this heat wave. (Temps will drop by 15 degrees on Wednesday). I had watered them well yesterday and this morning. They were looking stressed by this afternoon. I checked the soil under and around the plants and it was moist. I do have excellent drainage.
Soooooo that tells me to just go ahead and buy a plant at near full price and plan on dividing it down the road when temps are cooler.
It's a case of listening to the plant and doing what it wants to do instead of what I want to do ...
