What sorts of plants or trees do bees naturally collect pollen from in the autumn, or right before the winter? If there are no vegetative plants, like squash or eggplant, what sorts of trees or shrubs do they target?
Same here Golden rod, Asters, Golden Rain tree. Golden Rod and Aster are native to most of the U.S. there are several different varieties. Some locals like South Florida have a major flow from Brazilian Pepper. Up in the North they get a good flow from farmers growing Rape. I'm sure other place have some specialized plants that produce a good flow in the fall. But, you will have to ask some local Beeks if your area has any.