Q.Sudden Drooping Of Purple Leaf Sandcherry
This is the second season for my purple leaf sandcherry, it was planted early spring last year. This year, it looked like it was growing normally for it’s second season, however, today, there was a sudden drooping of branches. First pic was taken in the morning, prior to planting some annuals in the bed, adding a bit of fertilizer, watering and mulching. By afternoon, the stems were drooping badly, as seen in the second picture. Does anyone have any ideas what might have caused this?

Certified GKH Gardening Expert
I suspect it is related to the actions you took that day, and it could be that the roots were damaged when the annuals were planted. Was much digging involved? Either that or it was overfertilized. Go ahead and water well to flush out excess fertilizer if you think that may have happened. If the roots were damaged, the extra water will help it recover. This article should help:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/fertilizer-burn-in-gardens.htm
Sand plums typically reach 8 feet tall and wide, so it may outgrow that area soon. Once it recovers, you might consider moving it. Here is more on its care:
https://www.gardeningknowhow.com/ornamental/trees/sand-cherry/purple-leaf-sandcherry-info.htm