Catnip not just for cats
Catnip, like every other mint, has a short self life. The volatile oils dissipate quickly. The fresh plant has the highest potency and even one little leaf will be stronger than a whole dried catnip mouse. The old catnip toy probably has lost all aroma and only reminds the cat of its former effect.
Before freeze-up, cut all catnip plants down and after drying them, place all cut parts into a pillowslip. Place it in the place where you want your cat to sleep. It is the only guaranteed way of getting the cat to sleep there. If you have trouble falling asleep, borrow the pillow. It works.
Catnip tea will help you to fall asleep. All relaxant herbs lose their effect on your system with repeated use. Only use it in an emergency.
To keep your cat from destroying the plants, use upside-down wire baskets over the herb. Let the cat chew on the parts which grow through the basket.