Just a thought, that it could actually be overwatering? We have 10 cherry
trees - 8 Bing and 2 Tartarian, planted in two parallel rows. One of the Bings started looking poorly this
spring, looking rather wilted with some leaves browning, so I was extra diligent with watering. It ended up dead. The nursery said it was most likely due to root rot caused by overwatering. He explained the clay soil could have caused poor drainage in that one spot - even though the
trees are all together, and that the overwatering will cause the same "look" as not enough water.