I love daikon. Even if you do not get edible roots, on account of hardpan, you will open corridors down for the water to flow, and bees and children love the flowers. I am also fond of water cress, which takes care of itself well. Rocket is the same or very close to arugula. Arugula may wilt in snow but comes back as soon as it warms, and I love it, especially the flowers. Violets can somewhat get away from you, but they are lovely to have around. Both flowers and greens are edible, and they are quite cold-hardy. Garlic cannot be held down in my Portland garden, even surviving quite cold periods, poking its strong green leaves up. There are many kinds of garlic. Some of them "walk" which is to say, the flowers will make very cute little bulblets, if left to do so. I really like perennial collards, if you can find them. They look like strong palm trees in the winter, and the leaves are good to make minimal-hassle wraps with, if you are into high-fiber, low-carb wraps. I also like mallows to have around, if they are a choice for your area. Common mallow stays close to the ground. There is a small, wild-type strawberry with good though small fruit and bright pink blooms. It is decorative and it will travel. It is called lipstick. I like it a lot. Pineapple sage is not very cold hardy, so if you want a mint choice that will not take you over and that has pretty red blossoms late in the season, I would go for some of this. I am happy to have regular mints around, despite their bad rep for taking over. They do till, and if and when you have to wrestle with them, at least you are pleasantly fragrant afterwards. I like orange mint a lot, but it is out-competed by spearmint, lemon balm, and peppermint. Some of the worts are kind of stickery and not so much fun, but some people like them. I have some motherwort that planted itself, and I let it stay. Some people like docks. I find them rude, but I put up with them. They do send deep roots that help you to keep water on site, I guess. I am in favor of keeping the ground covered. If you have mulch, say a passion vine that will die down, you can cover an area and put potatoes underneath. One Thanksgiving when potatoes ran out, I ran out, pulled up the mulch and harvested a few. I do like to grow potatoes that way or in sacks because I don't like having to dig for them or cutting straight through some pretty ones. The rainbow chards are nice. I like how neon the colors can be. I like that in winter.