I need help. I bought 6 fig trees. One is still with me after 3 1/2 yrs, but I never had fruit on it. It's over 4 feet tall, and I bring it in over winter. I live in Illinois, 45 miles south from Chicago. I used root grow 4-10-3 a lot on it. It makes it grow better, but no fruit. I have another new fig tree that's a foot tall and it has fruit on it, so why is my large fig tree not fruiting? Is it because of root grow? I use it to get it to grow better. The other fig tree, my new one, is a year old. I just got it 3 months ago. The leaves fall off, so I did not know if it was dying or not so I used root grow on it. It helped a lot but now it has a white trunk and leaves. Doesn't look that good and a little brown in spots. Hope you can help.
For the non-fruiting fig, it may be a nitrogen/phosphorus imbalance in the soil. Too much nitrogen and too little phosphorus can result in little to no blooming, which means no fruit. This article should help: https://www.gardeningknowhow.com/edible/fruits/figs/fig-tree-is-producing-fruit.htm
For the other fig, the leaves dropping sounds like a fungus. Start the tree on a fungicide treatment. Also, make sure to clean up and dispose of any fallen leaves.
I have a fig tree which has been producing figs for the 30 years I have lived in this house. It lost all its leaves and did not produce figs either last year or this year. Normally it produces figs in July and August. Shall I cut it down? Please see the photo below.
It doesn't look too good. You can scratch off some of the bark and see if there is any green underneath. If so, it is still alive.
Here's an article that may help with your fig tree: https://www.gardeningknowhow.com/edible/fruits/figs/fig-tree-is-producing-fruit.htm