dieback of snow on the mountain ground cover

Question

For the past 2 summers the above plant has suffered considerable brown dieback in August. It’s planted on the west side of the house under a maple and is in shade all day except for the very southern edge, which doesn’t get brown and die. The plant recovers and regenerates before winter comes. What does it need to stop the dieback and browning? Thank you

Answer 1

Since the browning happens in August, it is possible that the plant needs more water to get through the hot part of the year. Another possibility is that the browning portion is old foliage that is less hardy. Mowing the plant one or several times during the growing season (before August) will encourage new, healthier growth and may prevent the plant from turning brown.

https://www.gardeningknowhow.com/ornamental/groundcover/snow-on-the-mountain/snow-on-the-mountain-plant.htm