Seed catalogs arrive in the dead of winter and quickly become a portal into a fantasy world right when I need it. But come March, the bounty they portray starts to seem tangible. One plant I have come to love is Mizuna greens (Brassica rapa ssp japonica). It can be sown with other spring greens, but unlike its rapacious peers, this dainty mustard green persists well into the growing season and can be harvested all the way to the first frost. It is a pick-and-grow style vegetable. Young leaves are great raw in salads or as a garnish. It can also be cooked like Chinese mustard or arugula.