Don’s Expert Answers: Black spot on roses

Question From:
Brooke in Manilla, Nsw New South Wales

Nature of problem:
Black spot on roses

Type of Plant (if known):
I have black spot on a couple of my rose bushes.

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself):
Black spot on leaves

Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type:
Clay/ loam

How often do you water the plant:
Once a week at this stage

How many hours of sunlight does the plant get each day:
8

How long since you planted it:
12months

Have you fertilised? If so, with what and when:
Thrive for roses

Is the plant indoors or outdoors:
Outdoors

Is the plant in a pot or in the ground:
Ground

What other treatments have you given the plant:
Regular cutting off & removing black spot leaves

Upload photo if available:

Other Comments:
I have black spot on my rose bush, as it is late autumn, I was wondering if I should winter prune my infected rose bush early, and treat plant with black spot spray, as cutting & removing infected leaves is not working?

Answer:
Hi Brooke, I am struggling with this. Back spot itself is not the problem (this why we beg people not to self-diagnose). The problem is why do your plants have black spot – in this regard I didn’t get enough info..Your saying “a couple” helped me a bit as did “cutting & removing infected leaves”. Cutting off lots of leaves could weaken any plant. And “a couple” of plants could point to these two being a weak variety. Roses that are well suited to your area should not get black spot. The humidity and rains over the last 9 months or so may be your problem too. Collecting the dead leaves as they fall and disposing of them in the garbage is a good idea to minimise the fungal spores being in the soil around the plants. If you wish to spray, use Eco Rose which is really only baking powder – ie very very safe. Don