I have a mock orange which is not doing well at all the leaves are curled and dry looking despite being watered. It is planted near 2 oleanders could they be toxic for the mock orange?
Oleanders won't be affecting at all. However, if they are doing well, then I suspect the conditions that suit them are a bit too hot and dry for the philadelphus. Tough though it is, it might have struggled for water at some point. It'll be fine once the weather changes,but chuck a bucket or two of water at it and see how it does. A bit late now as the leaves will be fading soon, anyway, but it won't do it any harm. A mulch next spring to conserve winter wet and provide a bit of food might be of use.
Thank you, I will give it a go.