I think I might be having the same problem with my "life of the party" heirloom rose. However mine has been in a pot for 3 months and was blooming at a fast rate. First picture is how beautiful they looked two months ago.
The leaves were growing out of the stem a beautiful dark red color and changing to a dark green. Now drooping, blooms don't finish, no smell, black on stems (cut back twice already to remove black and used glue to seal the cut) and my soil reader says the soil is dry and my PH is high. Leaves are light green with little development in growth then wilt and turn light brown. I bought the soil reader when I first got the rose and it has always shown a high PH even after I fertilized. Not sure if the PH reader is right. But I have done things like add coffee grounds and they bloom wonderfully when I do that.
Attached a few pics of how they look now and the reading for moist soil and the reading for PH. I recently got so upset over losing my roses I replanted them in new soil because I didn't know what else to do. Tried watering consistently and tried watering sparingly. Didn't change anything. Please help as I got these roses from Mississippi and brought them to my Florida home and they are special. Thanks for any help!
