Q.I Want To Plant A Purple Heuchera, But There Are Several Varieties. Which One Stays Purple ?
I have noted that there are several that are listed as purple, but some may change color. I am interested in something that will stay purple at least for as long as possible, and also wondering where I might find them and if it is too late to plant them.

Certified GKH Gardening Expert
I have 'Black Pearl' heuchera and it stays dark purple all summer. Others that should stay purple include 'Grape Expectations,' 'Dolce Wildberry,' Primo Wild Rose,' and 'Forever Purple.' The issue is so many new cultivars come out every year that nurseries can't stock them all and the one you want may be hard to find. Try reputable online nurseries but I'd stay away from individuals selling plants.
I would wait till spring to buy/plant them. It is getting late in the year and they need time to get established.
https://www.gardeningknowhow.com/ornamental/flowers/coral-bells/winterizing-heuchera-plants.htm
https://www.gardeningknowhow.com/ornamental/flowers/coral-bells/coral-bells-plant.htm