Blueberry Bushes Wilting and Dying
I have a 3000 square foot back yard in which I grow blueberry bushes in containers ranging in size from 3-gallon to 35-gallon. I use straight peat moss (I prefer MiracleGro) topped with pine bark mulch. I've used this setup for about four years. At random times, a few of my blueberry plants will suddenly begin wilting and die. This year, four of my plants, including some of my biggest, oldest and strongest bushes, suddenly wilted entirely and likely will die within the next two days. I don't see any evidence of insects or fungus. The soil is moist, perhaps too moist. I can't get a decent reading on pH, but my newly-bought pH meter says everything is almost 7. I've added several tablespoons of sulfur to all my bushes. Does anyone have any ideas what is causing this?