There are a number of cat repellants on the market. I think some of them smell almost as bad as the urine but I haven't tried them all. Try your local pet store for them or a good garden center.

Do you have boxwoods near the window? Some of them have an unpleasant smell and can remind you of cat urine.

I recently found "evidence" that cats had been using one of my flower beds as a litter box. The next time I pruned my very thorny roses, I dumped all of the clippings on that bed. Magic! No more cat visitors. Maybe you could protect your shrubs with something thorny and make them change their habits. I've also had some success with black pepper sprinkled around the perimeter.