Chemical Spray Burn on Roses
How to Recover
My roses were being invaded by aphids and other insects so my partner gave them a spray with Rogor (a systemic insecticide) and ever since then they have looked very sick and poorly.....coupled with the heat and the sun they look as if they are dying as some of the stems have gone brown.
What do you suggest I try to bring them back to life. I have had a few roses on a couple of bushes but they all look very deformed.
Any help you can give me I will be very appreciative.
Jackie - AustraliaBotanical Journeys Plant Guides
It sounds as if your roses are suffering from chemical burn.
I am not familiar with the specific product you used but spray burn happens when plants are sprayed with too strong a mixture of chemicals or when they are sprayed while the sun is shining on their leaves.
This can happen with any chemical. I once burned several plants in my yard by feeding them with too strong of a water soluble fertilizer.Even tap water can burn plant leaves if they are sprayed in very hot, sunny weather.
Spray burn often looks worse than it really is.The good news:
If the roses survive, they will fully recover from this unfortunate experience.The bad news:
The scorched leaves will not recover. In a few weeks, they will fall and be replaced by healthy new growth.
the brown stems. If the cambium layer just beneath the surface is green, they are still alive and will eventually produce healthy new leaves.
If the cambium layer is brown, the stem is dead. You may as well remove it.
How to Avoid Chemical Burn in the FutureIf aphids and/or red mites are your only pests, spray the plants with plain water in early morning or evening when the sun is NOT hot on the leaves.
A strong spray will knock the aphids off and most of them will not be able to climb back up onto the rose.
You may have to spray the plants 2-3 times to get them all.
If you don't use many chemicals in your yard, you should have enough beneficial insects to regain the upper hand over the bad bugs at this point.
Growing Roses Organically will provide more information about raising roses without chemicals.
Always follow the directions on the label when mixing garden chemicals. More is not always better.
The pre-mixed sprays that are sold in ready-to-use condition are safer in this respect.
Never spray foliage in very hot, sunny weather.
Good culture discourages insects and disease on roses. Well fed roses grown in the right climate on well prepared soil have far fewer problems.
Caring for Roses offers instruction for winter, spring, summer and fall rose care.
I'm sure that, with good care, your roses will go on to bloom more abundantly than ever!