Here are some temporary solutions for missing crockery. Every cat should have a WalkingJacket for emergencies, trips to the vet, rides in the car or carrier as well as a daily walk around the block. It's an indispensable part of every cat's wardrobe. Your cat will love the freedom and you'll have great fun with it too. Here's a great, inexpensive idea to help eliminate boredom in your housebound cats.
Some people take that to be an antisocial gesture and find it a reason to dislike cats.
However, it's very likely that cats are expressing fear. Hissing can make someone pause and take a step back. This allows the cat to back away and slink off. One interesting alternative to noxious and toxic weed killers is to pour some white, household vinegar into the grout lines and cracks of your outdoor sitting areas. It may be just enough to fend off emergent weeds while leaving the patio safe for the cats.