I am a casual gardener and live in Mission BC. I have miniature roses in a pot on the sundeck which has southern exposure and receives lots of sunlight. About 6 weeks ago, one of the roses developed Black Spot. I treated it with a Fungicide which seemed to help. I repeated as directed and the plant seems to have recovered from that. The problem I'm noticing now is that the petals on the roses are curled and the leaves are turning yellow and falling off. Any ideas??
Minature roses tend to have very poor root systems and as a result do not take up nutrient well. Looks like this is whats happened to your plant. I can't advise you on one way or another on what do but you might try repotting it in to a larger pot with some drainage in the bottom. Rose like a moist soil but not soggy and most minature roses are plunked into a peat medium to let the roots grow quicker. Peat will hold water and not drain well enough if you over water and it will also dry out fast in hot weather especially if it's in a plastic pot. All roses no matter what will loss their lower leaves as they grow taller.
It looks like powdery mildew by the look of the leaves. You can see it on the leaf top left. As Greg says though roses do get yellow leaves and drop offs.
Thank you Greg. As a matter of fact, it is planted in peat moss as well as being in a plastic tub. I was told the peat moss would be fine by garden centre staff and was warned to watch carefully as the soil would dry quickly. The overwatering and soggy soil wasn't mentioned though. This condition was noticed after a horrendous thunderstorm and massive downpour which drenched the plants the same day they were watered. I think you've likely identified the problem. Thanks so much. I'll watch soil conditions more carefully and re-pot if necessary. Appreciate your assistance. CG
