Does Triple 13 fertilizer cause black spot disease in roses? My Knock Out roses were really nice before I fertilized. Now ...

An expert rosarian offers advice on how to block or minimize powdery mildew, black spot, rust and more in San Diego gardens.

Q: I planted these Knockout roses two years ago. They did fine for a while, but this year they have struggled. I treated them with a name-brand insecticide and fertilized and watered them as well, but ...

Q. I have noticed for a few weeks now, my Knock Out Rose bush is producing some weird looking growth and the sparse blooms are distorted. How do I treat this? Will my Hybrid teas be affected? — C.

Roses are one of the most popular landscape plants, but many homeowners are unfamiliar with the most common rose problems. Rose slug, blackspot, rose rosette and powdery mildew can all have either ...

Last year, I noticed the yellowing and spotting of some of the leaves on my Knock Out roses. The same thing is happening this year. Can you diagnose and suggest what to use? For some reason, I thought ...