Answer: Groundhogs are discouraging!
In my experience they will eat just about anything and will damage other plants on their way to their favorites, especially where the population is high. They have large teeth and healthy appetites and no discriminating palate to speak of. In addition, these are unpredictable and potentially very dangerous wild animals, so I would urge you to consider some other measures and to be very careful.
Having said that, however, some of the more pungent plants such as the artemesias, some of the woodier plants such as Russian Sage, and some of the less tenderly succulent plants such as sedum might have a better chance.
Good luck with your perennials!
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