Powdery mildew

[sleepwhenimred]

I've just noticed my rose bush has powdery mildew. Can anyone recommend the best treatment for this please?

No idea.
My scabious get this too.

I thought it might be location as google suggested overcrowding and dampness as a factor (I had a bunch next to the pond) so I moved it to a better draining, drier spot and better spaced out but I noticed yesterday the start of mildew again!
Frustrating.

Following as my calendula has also got this :-(

I’ve had varying success with tea tree oil in a spray bottle with a couple of drops of ecover wash up liquid( makes the solution stick).
But it’s hard with all this rain as it keeps getting washed off.
It’s worked best on holly hocks

I have cut loads of mildew off but hope there are some other things to do

It's usually a result of a combination of dry roots (from the earlier dry spells this spring) and humid air. So keeping stuff watered in dry periods, and not too crowded so air can move around and evaporate the extra moisture.

Some things it's best just to prune out the mildewed shoots and let new shoots grow.

I found spraying with a weak solution of Ecover washing up liquid with a teaspoon of baking soda in a plant spray -mines the usual size one sold in garden centres- has kept it at bay.Plus killed the aphids that were also on my rose.I cut off the worst affected leaves then gave it a good misting from above and under the leaves.Remember to thoroughly clean your secateurs after or it will spread to other plants.