Most garden deer control methods fail because deer, especially the whitetail, are smart and highly adaptable and they quickly figure out that most deterrent devices will not actually harm them.
Garden deer control methods include:
Odor repellents to treat the area
Contact repellents to make the plants distasteful
Noise making devices and other scare devices
Water spraying devices activated by a motion sensor
Dozens of homemade devices invented by afflicted gardeners everywhere
Few of these approaches work for very long. Deer resistant or deer proof plants hardly exist because there are only a few plants that a hungry deer won't eat.
Deer control in the garden using a sturdy perimeter fence 7-8 feet tall is best, providing 100% deer control for any garden. Other permanent fences also work, like a slanted fence or a blind fence the deer can't see over.
Electric fences around the garden work well to train the deer to stay away if you can get the deer to touch the wire. The problem is the deer will often just jump over the fence without touching it unless the fence is very tall. If it is a baited electric fence, the deer will touch the wire and be trained to stay away whenever they smell the peanut butter or other scent used to bait the fence. The Wireless Deer Fence® works like a baited electric fence, but there are no wires to deal with.
Garden deer control methods become ineffective because the control method does not provide a sufficiently negative stimulus to compete with hunger and the deer will not stay away. Deer hate to be shocked; they remember it. Deer are adaptable to coexist with humans, and it takes a very unpleasant experience to overcome their nonchalant attitude as they munch a garden. A shock to the nose works great for this.