Perennial vegetables... yes I like that drift. If asparagus likes your soil, I bet you'll do great with the onions and garlic. I wish my Egyptian onions were next to an asparagus bed!
I have a couple of varieties of green onions which are supposedly perennial - Hardy Evergreen and another unnamed variety, which I'm leaving in the field as an experiment this year, along with some American Flag leeks of various age groups.... a colony of leeks if you like.
Still hoping for self seedng celery here, they are taking forever to be done wtih their mass of flowers.