I have been to Asheville many years ago and realize that fall foliage begins in the higher elevations and descends toward the Asheville area but am looking at what would be considered either too early or in fact too late to see the changing of the leaves.
September may be a bit too early but it will have started. November is probably too late especially if we have a lot of rain or wind. October is your best bet but it does vary from year to year. This past fall was the most brilliant I can remember in quite some time.
Book early! And prepare for congestion on the back roads!
Each year it can vary by weeks so it's really hard to know months in advance. Here's one site I use and this link has the high and peak time for the Asheville area for last year, which was late October.
https://thefoliagereport.com/blog-post/report-as-of-october-25th-2021/