Rose leaves have a problem, help me figure it out

[LT]

Hi,

I have a large Queen Elizabeth rose bush, it's probably 8' tall. Some of the leaves are turning yellow. I have a picture of the underside of these leaves here.

What is this and how do I 'cure' it?

Thanks in advfance, Laura

[Timothy]

This is rust. You will want to clean all fallen leaves from the flower bed. Do not compost the infested leaves. Burn them, bag and trash them or take them to a commercial composter.

To get rid of the rust you will want to get a fungicide that has copper or sulfur. I tend to select copper spray during the growing season and sulfur spray for domant spraying. I've had issues using sulfur on actively growing plant. This maybe just my experience with sulfur.... or the lack of, how ever you wish to view it. Good luck.

[Snooze]

Looks like you have rust and black mildew. You didn't say if it's still winter wherever you are. If so, prune back the plant, cut away the branches that have the biggest problems, then spray with a dormant oil or fungicide. (Not on a warm sunny day) Certain roses are prone to fungus and mildew problems.

Also how is this plant being watered? Drip irrigation? or an area sprayer? Try and reduce the amount of water that is sprayed onto the leaves, water early in the morning rather then in the evening, so the leaves have time to dry out.

Fungus spores are transferred via water droplets, so the less water on the leaves, the better.

[LT]

Thanks so much for your help!

I'm in the So. Bay Area in California, it's winter but it was a beautifiul day today. I picked oranges.

The rose is poorly located > > Hi,

[Snooze]

Ah, I'm in SJ as well. This past week has been rather warm. See if you can adjust the lawn sprinklers. Sprinklers tips, are designed for a spray pattern and a distance. Maybe go for a shorter throw pattern. Sprinklers also have a little screw on the top that can be used to adjust the throw distance.

Try that, given the size of your rose bush, relocating it is probably not an option.

-S