Thanks for writing. There's no real guaranteed list of rabbit/groundhog proof plants as personal tastes range from animal to animal. But in general, they don't like plants that have strongly scented foliage (catmint, bee balm, etc.), plants that have furry or fuzzy foliage (lamb's ears, wooly thyme, etc.), or that are highly poisonous (monkshood, hellebore, angel's trumpet, etc.).
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---Justin, Senior Garden Editor, BHG.com