What are "the usual applications"? And how many cups of Mills Mix have you applied?

I fertilize with good results until around Oct. 1. Others in zone 6-7 think you should stop around Sept. 1.

The issue of timing mainly involves nitrogen. Available (soluble) nitrogen is transient in the soil and will wash out in a few weeks. Therefore fertilizers with only fast (available/soluble) N are usually labeled for application every 4-6 weeks. Four weeks is appropriate for poor sandy soils and heavy rain or irrigation.

But organic fertilizers release soluble nitrogen gradually over a year or two. Coated timed-release products release it for 3, 6, or 9 months, as labelled.

The other fertilizer nutrients will persist in the soil if there is some clay content.

Thanks Michael - When I applied the Magic Mix I used 2 cups per bush both times. I've been using the Mills Easy Feed fertilizer, probably averaging about every 4 to 5 weeks.

There is probably enough slow nitrogen in the 4 cups of Mills Mix to carry into November, when the roses will stop because of the cold. But I would probably give another dose of Easy Feed (or 1 TB lawn fertilizer) if I were doing it.

Thanks again Michael, appreciate it.

With organic fertilizers, they are dependent on soil temperature for the microbes to break it down.So when the soil temps drop in the fall your fertilizer just sits there until spring. That is why I like to use it.
I use Monty's Joy Juice which is 95% organic. I will fertilize just one more time before I quit for the year.