Zone 45150 | Anonymous added on May 29, 2017 | Answered

Can you re-apply a pre-emergent, once shrub roses are blooming? Have black/brown spots on leaves and leaves look like something is eating on them.

A.Answers to this queston: Add Answer
Certified GKH Gardening Expert
Answered on May 30, 2017

I would give the rosebushes a treatment of Bayer Tree and Shrub Granules per the label instructions for Ornamentals/Roses. It is a systemic disease control product and has some food in it too so that it helps strengthen the bush to help fight the disease attack. A pre-emergent usually refers to an herbicide which is not what is wanted here, so I am assuming that you mean a systemic. Yes you can reapply systemics once blooming has started. If the rosebushes turn out to have black spot fungus attacking them, you may need to spray them with a product called Mancozeb, it is available on and will stop most black spot attacks in their tracks.

Was this answer useful?

Log in or sign up to help answer this question.
Did you find this helpful? Share it with your friends!

You must be logged into your account to answer a question.

If you don't have an account sign up for an account now.

Looking for more?
here are more questions about...
Join Us - Sign up to get all the latest gardening tips!

Do you know a lot about gardening?
Become a GKH Gardening Expert

Learn More