I'm getting dead boxwood sections destroyed hollowed-out trunk of sections of my boxwood shrub. I have been trying for years to figure out what insects or disease are destroying many sections of my boxwood shrub causing large sections to die out.

Today I tore off part of the trunk of one dead section and found that the trunk disintegrated in my hand because it was dead and hollowed out. When I placed it on the cement, out came a hundred ants pulling out their larvas trying to save them. Are ants destroying my boxwood shrub? A guy at Home Depot thought it was mites, and I sprayed all my shrubs for mites, but it hasn't helped.

Please let me know you know what's causing this. I didn't know ants killed plants, and one should I do about it?

In addition, a section where my boxwood died, I planted a new Boxwood shrub that was about 2 feet tall about a month ago, and it's now just about dead completely. What did I do wrong? It got plenty of water and sun, and I surrounded it with lots of store-bought soil mixed with some hummus. I don't think the bugs got to it yet. It just seemed to have not made it and shriveled up.

Thank you so much for your forth-coming advice.