That's the first time I've heard that one. As far as I know, any rose is either black spot resistant or not. I've been growing mini's for over 30 years and have grocery store mini's mixed right in with all the other mini's. Everyone is happy together but I also spray for black spot every 2 wks. I have found that over 90% of mini's are black spot prone. So I spray to keep the roses AND me happy.

Great! Thanks. I've never been in a black spot prone area before so a spraying program has never been necessary. I'll just hit all of them every couple of weeks and I should be good then.

I think the comment is related to the supplier. Box stores tend to get from suppliers who may have affected stock, whereas we hope nurseries have a better supplier. However, either could be true of any stock, depending on the origins. Or the plant could possibly even get the black spot later because of being not as resistant.

I would suggest you could label the plants and keep track of where they were bought from, for your own knowledge. That will give you an idea of how much you would like or trust the stores you bought them from.

It makes no difference, minis are minis no matter where they come from. Some get blackspot and some don't. The latter are rare. Most minis in general are rather prone to BS. I'm not sure why but it's pretty much a fact. I have my own idea that it's partly due to their being shorter, closer to the soil where a lot of the spores are, and that their branches/leaves are usually denser packed so there is less air circulation through the plant so they stay damper longer allowing the spores to flourish. But that's just my opinion. If your area has a blackspot problem then any roses that are prone to it will probably get it. The spores are already out there in the air, water, soil and other plants in the your yard.

We have had 2.5 solid weeks of rain, sleet or snow every day. Very little sun at all. My entire yard is standing in water. The ground is saturated and the water has nowhere to go. Today is the first day with no precip allowing me to be able to spray and I discovered I already have one mini with BS. This particular mini came from an excellent supplier with a stellar reputation. It is the only one showing any problems. The grocery store minis are all in tip top shape. Expecting rain the next three days again. This is the wettest start of the year in several years so it will be interesting trying to keep BS under control.