My bird's property is a little over half an acre in there I have day lillies they walk through them and nibble on them when they start to grow in spring but those lillies are tough they always make it through and bloom. I also have some irises they tromp them down but some manage to stay upright...
Flowering shrubs might work. You'd just have to research what is safe.
anything you don't want to be eaten or tromped down could always have decorative fencing put around.