@lauriebasler, Laurie ...
I'd love to give you more time and ask more questions about your heucheras, but I am having a very time stressed week, but I have a hunch giving them a lot of compost is the wrong direction for heucheras. Of course, I am a newbie and what do I know ?
The species heucheras are found in rocky, lean soils. When I planted mine, I put a lot of native soil, crushed rock and decomposed granite in the planting hole. I put the compost rich soil just in the top few inches of the planting hole where most plant's feeder roots are located. Again, in nature, nutrient rich soil and water is usually found on top of rocky soils.
In winter, I plop some leaves on top of them and forget them. In spring, I push the leaves back and feed them a little bulb food.
That's the good care I give them. Then, I mess up. They are in a corner of the garden where I tend to get to them last ...
so they don't get watered regularly and often get dry and I happen to walk by and get one of those "OMG" moments and put a hose on them to dribble water on them to give them a good soaking.
I've been meaning to divide them for the last two years, but health-wise I haven't been playing at 100%, so that has been one of my pending items. I can't say they are thriving, but they are not dying. I think if I got them divided, they would be much happier ...
Based on my neglect ... and that has been pretty consistent ... I find myself asking if you are killing them with kindness ?
Just a thought.
If you tell me which ones you have tried, when I have more time, I have a spreadsheet I made up with the lineage of many of the heucheras to give me an idea as to which ones might do best in a more arid climate. I'd be happy to share my guesses.
This is 'Amathyst Myst' and it has needed to be divided for the last three years. It keeps coming back.