I have several Kira Garden heucheras. The leaves are getting brown and drying on edges. I water them frequently. Are they perhaps getting too much sun?

Too much water will cause browning on the leaf edges. A plant pushes water through to the edge of its leaves, and if given in excess, this can cause veins at the edges to burst, which leads to browning. Reduce the frequency of water and extend the amount of dry time between waterings.