Why won’t my rose flowers open and why do the leaves look like they are dying?

There are tiny little sap sucking insects that are in plague proportions across Perth causing significant damage to every rose bush they can find which is most of them in gardens around Perth. They have been identified as Chili thrips (Scirtothrips dorsalis) by the Department of Agriculture. The summer rainfall and humidity has caused conditions for them to explode in numbers and spread across the Perth metropolitan area. The leaves look like they have been in contact with herbicide spray drift and are wrinkled leaves with brown scarring while the flowers are failing to open.

If you take a closed flower and open it up on a piece of paper, you can see the thrips if you look carefully. They are 1-2mm and range from light brown in colour to black.

Once they have arrived it’s too late to try and save the existing foliage/flowers so it’s best to do a hard prune to encourage new growth and then spray the new foliage with a systemic herbicide.

Please see your local nursery for help on controlling thrips.