The smell that cats hate are rosemary and thyme.
Cat's also hate the smells of mustard and banana and eucalyptus and lavender.
If you want to keep your cat away from certain areas you can use rosemary or thyme or lavender or eucalyptus to keep them away from certain areas.
Cats are very sensitive when it comes to smells and they hate some scents more than others.
To keep cats out of yards or gardens, plant the herb rue or sprinkle dried rue.
Citrus or lemon scents (orange peels, lemon peels), garlic, ammonia, vinegar, coffee grinds, pipe tobacco, mustard, citronella, or eucalyptus all deter cats as well.
A good homemade cat repellent is to mix together lemon juice, rosemary and white vinegar – three things cats detest.
Put the liquid in a spray bottle so it's easy to use around the garden.
Simply spray near where the cats spend time on planters, the patio, or even inside.