The only way I've got anything established with ducks around has been to put chicken wire around it - at least it doesn't need to be as high as for the geese (who have ring barked my baby fruit trees - grrrr). I thought gooseberry might work but even the thorns on them didn't deter munching ducks. They're pretty good at digging things up too. They've got raspberries through the fence (starting with the bits that poke in and pulling the rest through), taken the top out of a grapevine and I've let them free onto the pumpkin patch post-harvest which they've turned over nicely. Oh, except for the thistles. So thistles?
H