I am not familiar with how hard the ground freezes up north where you are. Could you pour warm water around the plant and into the root zone, and dig it up?
Actually, I think what I would do would be to buy new iris bulbs or rhizomes, and new garlic. Perhaps trying the warm water for the ornamental grass. You can cut the grass down to just a 'crew cut'.

My budget really can't accommodate replacing all these plants. I spent a lot on the garlic, and really don't want to lose the whole year's crop. Especially since whoever moves in probably will just mow everything down. I got the same idea about the warm water from someone on twitter too. They suggested running a hose from inside with continuous warm water, and then digging up. I think that might be worth a try. Definitely getting the garlic and the grasses...If I have to leave anything, it will probably be the iris. I was renting, you see, so I have no incentive to leave anything for the person buying the house. Luckily, I'm buying my new house, so hopefully won't have this problem ever again. Thanks.