Answer: Since fertilizer promotes new growth, you don't want to wait too late to feed because the new growth won't have a chance to harden off before cold weather arrives. You didn't mention where you're gardening so I can't give a positive yes or no, but can give general guidance as to whether or not it's too late in the season. If you still have 6-8 weeks of good weather before the first frost, you can feed now. If you expect a frost prior to that, wait until next spring to feed.
Best wishes with your azaleas!
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