I'm thinking of buying some bulk African Marigold seeds and sowing them along the fence for some color this fall; wondering how they grow down here?

I say: go for it!

I grew some a few years ago and they did very well. I still have a volunteer seedling that came up this year. I am sure I would have had more but I had treated this particular bed with preen as I had changed plans for that area.

Yes, they'll do well for you, at least through the fall well into spring if you don't get a freeze. Sometimes they peter out in the summer heat and humidity, though, but collect some seeds as 'insurance' and you'll have them again for most of the year.

Honestly, mine bloomed for most of the year and reseeded itself until I used preen in that bed.

We had the same going on at the school garden, marigolds growing all around the perimeter. I taught the kids to collect and distribute the seeds, too.

Until one summer they all just disappeared, and never returned - not a single seedling! I assumed it was lack of rain when they were making seeds, or something. But it may have been the bunnies returned, because the gate was left open, or some other critter ate them.

If it's a reputable seed supplier, I say go for it! I grew African Marigold (Tagetes erecta) from seed when we lived in the zone 9b Daytona Beach area and they produced numerous seeds and plants each year.