rose trees

[rover218]

what is the best treatmemt for black spots on roses

[Clanad]

Black Spot is a fungus that can overwinter and in the Spring begin to produce spores that move up the rose plant. It produces, as the name implies, black spots on leaves which then turn yellow and fall off. It can and will denude the entire rose if unchecked. The best course is to eliminate the spores before they can gain a foothold. In the spring, before the first sign of new growth on the rose is observed, clean the area of left over leaves and other debris and spray the area at least a foot out from the drip line of the rose with a product we call here in the U.S. Dormant Oil. It's readily available under many brand names. It's a foul smelling, sulphurous concotion you mix with water in a hand sprayer, but it works really well. (Don't get any on good shoes, 'cause you'll never wear them outside of the garden again). It is non- toxic. If Black Spot is seen during the summer season, there are many good anti-fungal sprays. My favorite is made from Neem oil. I like it since it's environmentally friendly and adds a nice shine to the rose leaves. Whatever you use, be aggressive, spraying the plant at least once per week until no new signs are seen. If it should persist, prune severely...
Try not to water the roses in the heat of the day and try not to get water on the upper, leafy part of the plant, but water it near the surface.
Best of luck!

[dunr]

Paint them another colour!

[Hawkwalk]

Rose Clear - available in most UK Garden Centres.