I love the concept of perennial vegetables! I plan on filling my hugelkultur bed with them, over time… asparagus, artichokes, cardoons, more sorrel, herbs, etc. Incidentally, large, lemony sorrel leaves make amazing ‘lettuce’ wrap substitutes to fill with tuna or egg salad. (Spicy, larger nasturtium leaves, though annual, can be used the same way) they’re both delicious!