Squirrels also have a tendency to fixate one type of plant, I don't really know why, but I have found that it is usually an annual. If we have a plant that we have had to re-plant more than 3 times, we get more of the same, that plant is the plant of the year. By doing this they leave other plants alone. Oh squirrels can see in color, one of the few mammals besides humans that have this ability, they like red and pink! They also favor young plants.