All my roses went bonkers for this stuff—even a rose that has made maybe four or five flowers a year as long as I’ve lived here is suddenly throwing out dozens. Definitely worth the try!!
I have been growing roses for over 35 years and just recently discovered this product and it is the most complete and effective fertilizer for established roses I have ever used. I apply it regularly throughout the growing season and am amazed at the results! I am located in zone 8.
I think the 15-10-10 formula is key. I have used mostly organic fertilizers for the 200 roses that I take care of on our church campus in zone 8b in the Pacific Northwest. Sometimes I add iron or alfalfa pellets when the rose leaves look pale. I had 9 roses in a group that were not responding to my usual extras and kept their pale leaves and less blooming. They were Kaffe Fassett and Blueberry Hill- very reliable three year old roses. So I bought the fertilizer sold here by Heirloom and applied it at the end of July and the roses took off growing with lush green leaves and plenty of blooms. I have since then been buying the fertilizer during sales and storing it for my spring application. A rose expert friend of mine who helps me at church said roses need that extra nitrogen which is the 15 number on the label. Nobody else sells that 15-10-10 combo. This is the place to get it. There are also other ingredients in the fertilizer that more mature roses like. Definitely worth the money. One 8 pound container goes a long way as you use 1/2 cup per plant.
I've tried LOTS of different rose fertilizers and this is by FAR the BEST!!! Each of the roses (60+ - teas, grandifloras, climbers, floribundas... zone 7b/8)) have grown at least one new cane, and the foliage is much more resistant to black spot this season after the application of this rose food. I will not buy any other rose fertilizer from now on!