Q.sand cherry bush
is very skimpy looking as in sick not much leaf, but leafs do not fall off

Plant sand cherries in a bed with full sun and fertile, fast-draining soil to encourage dense foliage growth and a deep, penetrating root system. Avoid planting them under overhanging shrubbery or trees since the shade and lack of air circulation will encourage insect pests and disease.
Feed sand cherries yearly in early spring before new growth emerges. Apply a 12-12-12 fertilizer at half strength around the base of the trunk. Water slowly and deeply after feeding to push the fertilizer deep into the soil.
https://www.gardeningknowhow.com/ornamental/trees/sand-cherry/purple-leaf-sandcherry-info.htm