One of the major challenges we face in planting in Marin and Sonoma Counties is deer. The wooded slopes and open space are beautiful amenities to the local community, but also serve as great habitat for deer. In most areas any unfenced plantings need to be deer resistant. Notice that I say resistant and not deer proof. This is a major distinction. Just because a plant is on a deer resistant list does not mean it is deer proof. If the conditions are right deer can and will eat almost anything. This is not to say that there are not some plants that deer will rarely eat, but there is no such thing as a deer proof plant.
One product that we use on newly planted material (deer love juvenile foliage on plants they are not supposed to eat) is Liquid Fence. It is a deer repellant designed to be applied frequently at first, and then periodically once deer have been “trained” to stay away from your plants. We have found this product to be a moderately effective solution to deer “proofing” plantings if applications are made regularly.