One herb that is particularly repelling to cats is rue (Ruta Graveolens). Rue is a semi-woody perennial that grows to about 2-3 high and wide. Rue has gray-green foliage and clusters of small yellow flowers in summer. It is hardy in zones 4-9. Rue prefers full sun and, once established, can grow in poor soils and hot dry sites. Rue will repel cats from the area in which it grows. In addition, you could sprinkle the leaves of dried rue in flower pots or other areas you would like to protect from cats. You could also spray your existing plants with I Must Garden Dog & Cat Repellent. It dries clear and won’t harm your plants and your cats will stay away!