"The best solution (and the most expensive) is a stout fence to keep the armadillos out. If you take this route, make sure the fence is extended a foot or more into the ground, or the ’dillos might just burrow under it. You can also try an ultrasonic pest deterrent device. A few different models promise to remove armadillos, skunks, and other visitors from your yard. A less expensive method (that won’t annoy your dog or cat by accident, as an ultrasonic device can do) is to simply make the areas they dig in smell bad to the armadillo.
Armadillos have sensitive noses. (The armadillo’s olfactory bulbs " the part of the brain that detects odor " is about 1/3rd the size of their cerebrum, the part of the brain used for thought, learning and memory.) Anything with a strong, noxious odor can help evict an armadillo from a den. Mothballs have been used successfully in the past, and I have also heard that some armadillos do not like the smell of pine needles or pine mulch (they avoid foraging in areas with needles). Placing mothballs around the areas you most want to protect can keep pesky burrowers away. Peppering your whole lawn with them might be a bit drastic, but they might help you save your flower garden.'