Your acer bush is losing its leaves?

Massive, sudden leaf drop generally tracks back to root or watering problems. Roots may be food sources to underground critters. Or they may be growing back on themselves. Girdling strangles plants, so they can't take in nutrients and water. Soil moisture levels may be off. Adequately moist soil's moist, not waterlogged, 6" down. Break the year down into a series of 7-10 days. Soil may dry out whenever there hasn't been a rain or snow fall event within each 1 to 1-1/2 week block. Supplemental watering may then be called for.