I've grown sweet potatoes a few times now and pruning does not hurt them at all. in fact the leaves are edible and highly nutritious. they are commonly eaten in se asia and w africa. the tase is similar to spinach with a softer texture.

How do you cook them?

a woman at my job is from the philippines and she recommends blanching them very quickly then tossing with a bit of vinegar and onions for a salad. i gave her some leaves and okra from the garden a couple of weeks ago and she said she was going to cook both the same way and toss together. i've haven't tried this yet, though.

in the past, i've used them just like spinach. sauteed w/garlic, saag paneer, etc. i don't care for the smooth texture much so i usually only use them in smoothies and spinach bread.