Plants chewed at the bottom can also be the work of wood rats...seen 'em decimate plants..a good deer repellant can be made by taking a dozen eggs and cracking them into a container of some kind, adding some water and maybe some cayenne pepper, mixing it all up and letting it sit out in the sun for a few days...make sure the container has a ventilation hole or she'll blow scotty! It'll start to smell REAL rank--that's what you want--then use a kitchen strainer to pour the equivalent of 3 eggs to 2 gallons of water into a sprayer and spray the whole plant...deer are herbivores and don't like it...as for rats, traps are the way to go...if using the wooden ones they should be tied to something with some masonry twine or something or they'll disappear. Good Luck!