What plants can I use to repel deer? Also, what plants won't deer eat?

My best experience is to do multiple things. The deer will figure a way around just one thing (like the fence, though I'm sure it does help some). There is a deer repellent you can buy, but I like to make my own. Hot sauce, hot peppers - put anything hot in a blender with water. Blend. Strain (I use cheesecloth). Spray!

But there are also plants that deer don't like - and you can use these, or at least intersperse them between your other flowers. Deer don't eat daffodils, autumn sedum, pulmonaria (scratchy leaves), perennial geranium, sunpatiens (impatiens), etc. I plant my garden borders with many of these (and others), and it helps deter the deer.

Deer never touch my Pachysandra, Dianthus, Lily of the Valley

A farmer gave me a gross recipe for repellent...but it works. cup or two of urine, tablespoons of crushed garlic, and cayenne pepper, two eggs in a gallon jug, shake well, fill rest of the way with water. Cap and let age a week. Then you drizzle small stream around the perimeter of whatever you want to keep them from eating. Works on rabbits, too.

Deer like hosta plants when they are blooming but seems to let them alone otherwise. I spray them with a cup of milk mixed in 32 oz spray bottle filled with water. I've had good luck. Down side if it rains you need to respray. I spray anything fragrant including roses.