Perenial nitrogen fixers for Maryland

Hi, i started my journey to convert my yard to a food forest last year. I planted some fruit trees , and for every two fruit trees i planted an elderberry in the middle. I saw info that elderberries were nitrogen fixers, but recently i found a thread here in reddit that they are not. So now i am looking for a different plant to add to to mix, im going to keep the elderberries for now as they all survived haha. This year so far i added clover to the area. I would like to add a perenial shrub to assist with nitrogen fixing. What are the best options for Maryland? Zone 7. Bonus points if it has any of the following perks. (Not necessary to have all 3) 1. Edible 2. Naitive 3. Has pretty flowers