Accident with roses

Asked July 9, 2018, 8:44 PM EDT

I sprayed roses with a weed control instead of roses disease control by accident. Although I hosed them immediately, the leaves and some buds wilted and burnt. I cut and removed the most effected leaves. Question: what do I do now? In the future, what organic spray would you recommend? Please photos attached.

Washington County Oregon roses herbicide damage abiotic issues

5 Responses

A few questions for you about the herbicide (weed control):
1. Which herbicide (weed control) did you use?
2. What is the active ingredient or product name?
3. How long ago was it applied?
4. What problem do you need to resolve - Insect(s) and/or disease(s)?

I look forward to receiving your information.






I attach an image of the herbicide with the list of ingredients. I used the spray a month ago. I am fighting diseases like black spot, rust, and powdery mildew.

Thank you for sending the additional information.

The label says it’s “Rainproof in 15 minutes” – so, if you hosed off the spray before that, you may have lucked out. The roses may outgrow the effects of the weed killer. (Let’s hope you did a poor job of spray coverage, also that you hosed it off in time!)

In the end, only time will tell.

While you wait, continue to water normally. Don’t fertilize until the shrub returns to healthy growth, which may not occur until next spring.

In the northwest, roses commonly are attacked by various diseases. Most common are black spot and powdery mildew. Rust may be a problem, also, especially if the shrub is watered from overhead, such as from a sprinkler or a hand-held hose.

If you decide to replace the roses, be certain to ask for kinds with disease-resistance. Resistance is the best kind of “organic protection” when combined with full sun (at least 6 hours daily; more is better); sufficient soil moisture (add an organic mulch to help conserve supplemental moisture); and excellent air circulation (not adjacent to a hedge or fence).

When disease does appear, it must be treated at the very first indication. Then, contact the Washington Master Gardener office via email. (mastergardener.wc@oregonstate.edu)

When you email, please include images of the problem. The most useful will be 1. The plant and its surroundings; 2. The affected plant overall; and 3. A close view of a stem with both healthy and affected leaves.





I hosed the roses right away and now I can see that they are coming back. There are new buds and new leaves; also there are new shoots from the bottom or from the root. Unfortunately, I fertilized the bushes which seemed to help. Thank you.

I'm pleased to know that the roses seem to be turning the corner toward recovery.

Caution: If the roses are grafted – the usual condition for purchased roses – it’s important to remove new shoots that grow from the root or from below the graft union. Those stems won’t produce the same flowers as the top growth will.

Don't worry about the fertilizer at this point. But, in the future, know that it's not a good idea to fertilize stressed woody plants.

Even though it appears that fertilizer starts new growth, it doesn't. (Research with trees has shown that the energy used for those new stems and leaves comes from the plant's.) In other words, the plant is using up its "savings account" of stored energy, not the fertilizer.