I'm especially looking for productive vegetables that either have
striking foliage or flowers.

Thanks!

Artichokes, both globe and Jerusalem. Climbing peas or beans. Grapes.
Herbs. Many flowers are edible. Fruit trees. My personal favourite is the
globe artichoke for striking foliage. I like the quince tree for all round
beauty, it has great flowers, attractive leaves and good looking tasty
fruit.

David