Making some protective rosemary salt this morning. One European witch trick for protection is to spread salt (I use Kosher Salt) in front of your doorway to keep out people who mean to harm you. Rosemary is also an Italian witch herb for protection, and it's one I personally resonate with.
Each witchcraft tradition has its own method for protection. In Hoodoo practice, red brick dust is often used the same way salt is used. I recommend doing what resonates personally with you. If you don't believe that it works, then your intention isn't there and it might not fully work.
But if you're interested in working with herbs, here are a few you can use for protection. Choose the one that's your favorite or the name that stands out to you the most--it's getting your attention for a reason.
Some Protection herbs: fennel, dill, bamboo, coconut, bladderwrack, burdock, calendula, black pepper, hyacinth, gardenia, buckwheat, eucalyptus, marjoram, lime, geranium, coriander, holly, blue cohosh, iris, larkspur, aspen, foxglove, male fern, mistletoe, mugwort, acorn, sage, african violet, garlic, angelica, basil, rosemary, thyme, yarrow, rice, st. john's wort, poplar, tomato, stinging nettle, skullcap, toadflax, and periwinkle.