one of my rose bushes has black spots on ALL its leaves. I know that it is a fungal infection but I don't want to use chemicals. It would be difficult to cut all its leaves so I wonder if I could simply prune it now in the beginning of May?
What else can I do to fight this fungal infection? Some advise,please.
Not having the benefit of seeing a picture, my guess would be either downy mildew or black spot disease. Many people often confuse Black spot with Downy Mildew.
See picture and description of Downy Mildew here:
With Black Spot, some cultivars are far more prone to it than others.
prolonged humidity and dampness can aggravate it, luckily both diseases can be controlled without harsh chemicals. I use a product called Soap Shield with EXCELLENT results.
It is available through www.gardensalive.com.
I also tend to avoid cultivars that are
persistently problematic (especially with Black Spot)
Hybrid Teas are beautiful, but most (although not all) are a problem.
Most of the Rugosa roses are Black Spot free. Also Lady Elsie Mae, all the Knock Out roses, and MANY others.
Preventative maintenance is your best option, as Black Spot is much easier to prevent than control once it is present.