Here are a few suggestions for existing plants . . . you can place chicken wire beneath the base of the plants just below the soil surface and replace the soil back to the base of the plants, re-covering the roots. You can place thorned rose branches around the base of the plants as a form of prickly mulch. Soak hot peppers in a gallon jug overnight, strain it and fill a spray bottle and mist the plant leaves above and below. Fence the area, or create a fence circling the individual plant. Place a plastic predator (like a snake, owl or cat) near the plants.
Hope these help!