>>2683831For your region you can learn all the trees, understory trees, vines, and shrubs fairly easily if you just spend time in the woods. Where I live there are only a couple hundred major trees to get down.
Learning all the weeds, flowers, sedges etc. is much more difficult. In your area there are going to be a a few dozen that are common and easily identifiable- but beyond those you will need to learn the families to make any sense of the weeds. Go out into the woods in each season and pick a few you don't know and go home and compare them to an ID key and learn them. Go out with someone that knows them too.
Learning the plants is one thing, learning them in all seasons is another. It is easy to ID a plant when they are in spring or summer etc. IDing them in all seasons just takes time in the woods (ideally the same woods) so you can see them develop season over season. I've been in the same woods a few hours every other day and it probably took me five years or so before I could get 95% of trees shrubs etc. and I can probably ID 50% of the weeds etc. and place almost all of them in the right family. After enough time you will just get a "feel" for a plant and how it grows even if you don't memorize all the key ID traits etc.