Go to the dollar store and get the cheapest powdered Cayenne pepper. Shake it all over the shrub, preferably while the morning dew is still on, so it sticks. They'll learn quick, the shrub is no good to eat.
For my fruit trees I just made round hoops out of woven wire and set them around them, I also raised mine up so that I can mow under and around the plant, and a little piece of drain tile around the base to keep the rabbits from chewing on them. Ill see if I can find a picture.
All the really good ideas I've ever had came to me while I was milking a cow.
I have game cam pics of the deer standing on their hind legs to eat the tops off of trees in 5' tree tubes. I also have pics of them knocking down the tubes.
I have also set little barbed wire fence enclosures around my trees. It works well, but it utilizes a lot of materials AND it is a pain to climb through to weed or prune the trees.
I finally tried the patented GEHAJAKE Elevated Hoops System (as shown on some of the trees in his pic).
It works very well for the tree-deer situation on my farm. I give it two thumbs up!
(I have a $35 t-post puller from Tractor Supply that works superbly. When the trees finally grow out above the deer browsing height, it will be quite easy to remove the hoops and posts, and then re-use them on any new plantings.)