Yes, the plants can really work. Velvet, lavender, rosemary and alliums give off odors that are unpleasant for snakes. It is better to plant them on the perimeter of the plot or near the entrances to the garden and house. To enhance the effect can be combined with essential oils such as cinnamon, clove and cedar tree. If necessary, add granules or sprays with sulphur and naphthalene. It is also important to keep the plot clean and control rodents to reduce the interest of snakes in the garden. I can recommend read more about effective methods.