I have a garden bed, in which I have planted herbies. The first time I planted it, they grew well for 18 months and then one by one died. I thought it might have been a disease in the plants, so I went to a different nursery and got another 14 and replanted. They grow beautifully then one plants leaves started to charge again, eventually it died and all the others have died since. I went to a nursery and asked what she thought was going on. She said the only thing that could kill herbies is a soil fungus. She gave me something and I have treated the soil, but this didn't stop the last 4 plants from dying. what is killing my plants. I have other herbie in other parts of my garden and they are doing well.