Neptune,

You may want to look up Pierces disease. That disease is what keeps us in the deep south from growing northern cultivars. Hopefully that is not the issue. Check the map and see where you fall.....

Thanks, bamboo_rabbit. According to a map, Pierce's disease is rare in my area, northeast Georgia. That doesn't mean it's impossible, of course. But if it were that, wouldn't the other 2 grapevines get it within a month or so?

They should get it yes but just like people all plants are different and some are stronger than others. The cold is the limiting factor on the disease and with last winters warmer than average temps......

I am not seeing the map in my original post so will put it in here.

I grew up in northeastern PA which is a large concord growing area on the shores of Lake Erie.......it is where most all of the Welch's concord jelly comes from. I was bummed when I learned I could not grow Concords in Florida due to pierces disease. As good fortune would have it though there is a muscadine that tastes identical to the concord...Nesbitt. I will have fruit next year from it. Would have had fruit this year but removed all the flowers.

Just an option for you if your Concords do get pierces.

Thanks for the map--yes, I'm in the "rare" zone. Glad you'll get fruit next year from your Nesbitt--maybe removing the flowers will end up proving worth it. :) OK, thanks, I'll keep that open as an option.