The typical suspects would be rabbits and deer so, review the area and the damage up close to confirm. Rabbits sometimes leave distinctive round droppings and their damage can be identified by the height of the cut although, some fawns may also cause similar low cuts. A typical rabbit cut is anywhere from around 3 feet high to just a few inches high. Rabbits will cleanly cut the stems -usually- at a sharp angle. Since deer lack upper teeth, they nibble, tear and leave a ragged cut instead. Next, look “downwards”, in the vicinity of the affected plant(s). Deer scat can look pretty similar to rabbit scat although it tends to be darker and more oval in shape, and left in little piles. Rabbit scat is teeny brown, pea-like. Rabbits prefer still-green stems with leaves but deer do not care as long as it still has leaves. When spring arrives, hydrangeas that bloom on old wood may flower poorly if these pests cut the flower buds at the ends of the stems. Panicle and smooth hydrangeas will have the same blooming problem but only when pests graze closer to the summer months; a winter grazing session will not usually not decrease those species' summer flowering as those species -most of the time- do not have flower buds now. The roots of the shrubs are typically unaffected so maintain 3-4" of mulch at all times past the drip line. Continue watering and mulching. Consider sprays and fences around the shrubs.

Rabbits decimated some small hydrangeas in my backyard. I had to cage the plants until they got bigger. Deer are also a possibility.

i don't see any scat, yet chances are RABBIT was the one, as luis described the height of the cut. They are all very evenly cut with sharp angle.

What can I use? If not rain for a while, SPICY HOT water sprayed on the plant?//?? I used this method before, yet not very reliable, for sometimes forecast doesn't predict rain accurately.

Thanks

Plantskydd Animal Deterrent, Liquid Fence and other deterrent sprays. Or wire mesh around the shrubs at least 2 feet high and a few inches buried underground.