Call the city hall and ask them what the bylaws are and what restrictions you have. If you do things by the book, then the neighbors can't do a thing. Vancouver is pretty good about food gardening and even allow chickens in back yards. They seem to be very forward thinking and green conscious. Even if you neighbor is a p.i.t.a., during harvest go over and bring them a gift from your garden.
I have a neighbour whose backyard is really shady. For years I urged him to put veggies out front. He finally overcame his qualms & put a few under his sunny eaves. They grew really well. Now the whole front of his house is veggies. A lot of people have complimented his garden. There have been no negative comments. Beans up some poles, squash plants, Kale, Tomatoes & some lettuce scattered among them - it's very colourful & decorative, in my opinion. The distinction between veggies & ornamentals is a bit vague. Sometimes I can't find our herbs which are planted in a herbaceous perennial bed! Why not mix them up just as it suits YOU or ME?
I agree with Lysichiton that it can be lovely to mix it up. I think traditional cottage gardens were like that with flowers mixed with herbs, etc. However, I also agree with David Payne Terra Nova, that you should be aware of the rules. In Calgary (where I used to live) the rules about having a vegetable garden in the suburbs were....draconian, and I'm sure my neighbors would have complained if they'd had any opportunity. I grew corn in big barrel pots by my front door just to amuse myself.
