I began open feeding about 2 1/2 weeks ago, but my bees didn't really start to get at it until there was little if anything left for them, about a week now (goldenrods are done, asters are close). All that's left flowering in our garden is some purple mallows, that my bees usually love and some late blooming rambling roses, but bees are pretty much ignoring both over the syrup right now. All my colonies are busy with activity bringing in the syrup. My LONG Hive colony is still throwing out drones.
With the extended forecast looking at pleasent weather (above average temps) for next ten days, I'll be needing more sugar, that's for sure.
I honestly can't wait for winter.