IMO, the plant you are looking for is Lavender Starflower (Grewia occidentalis; sometimes sold as G. caffra). Zone 9a 9b 10a 10b. Sunset zones 8, 9, 12-24, H1, H2. You will want to espalier it against the fence, but they are one of the easiest plants to espalier--the branch form is naturally flat! My current plantings are in a narrow 13"-15" planting strip along the house, but I have used them in narrower beds. They may go into a bit of shock trimming the roots of a 1 gal plant to 4" wide for your footing reduction, but these are tough customers and I would not bet against them being able to overcome the rough start with a bit of extra care. Mine are currently about 8' tall and don't have any support other than resting against the side of our house, but a single horizontally strung wire would do the trick, if needed. They are generally listed as 6-10' height, but my SoCal experience is that espaliers easily reach 11'-15', if allowed. For all that, they are surprisingly quick and easy to keep pruned to form. They take heavy pruning like a champ, even hedging, and bounce right back. The foliage is a nice dark green, and the 1" lavender flowers that show up mainly in spring and fall are attractive and hummingbirds like them. Not messy plants--mine have never produced much litter. The plants grow quickly from 1 gal. size; they take a little while to get going, but then make up for lost time. They are heat tolerant, wind tolerant and, once they are established, drought resistant. Mine have never been bothered by pests or diseases.

Don't be fooled by the "sunny Saskatchewan" slogans. Keep in mind that Saskatoon is several degrees of latitude north of Toronto. Our winter days are shorter, significantly colder (average is about 10 degrees lower than in Toronto), and quite gloomy in the first half of winter. It's the second half of winter that you really start to see the sun. It's just that we have a greater *percentage* of sunshine in our winter days, and again, most of that is apparent in the second half of winter. Because our summer days are significantly longer than Toronto's, and with a somewhat higher percentage of sunshine in these months, we end up having a sunnier climate. I have a greenhouse but I wouldn't dream of using it from December through February. It's prohibitively expensive. Much better would be to adopt the ideas suggested by folks above to maximize the light captured by a non-greenhouse structure and supplement with artificial lighting. This will also help with cooling in the summertime. Another thing you'll have to get used to is that our summers are several degrees cooler and several weeks shorter than those of Toronto. Be prepared to handle freak frosts in early June. This means covering tender crops when required. Cool nights can occur anytime during the summer, so if you plan on growing anything that loves heat, you'll need an unheated greenhouse. If you can handle a 45 to 60 minute drive and budget for equipment, I strongly encourage you to think about buying a home instead of a condo. There's nothing that quite beats the exhilaration of having a large garden. This post was edited by Slimy_Okra on Mon, Mar 17, 14 at 19:58

Emerald Arb has a bit of a reputation of being more prone to winter burn then others, though I haven't had any problems to speak of. It is very tightly columnar, so doesn't knit together as well as others. I think Techny probably has the best overall look of all the arbs, dense but soft, and grows quickly, but will get fairly broad, 8 feet or so. Holmstrup is nice but grows slowly. I also really like the upright green junipers, like Spartan or Hetz Columnar. They have good berries and and dynamic texture if left unsheared. Also investigate the columnar forms of Scotch and White Pines or even plain old Black Hill's Spruce as part of the mix. Ted

What I've seen called "mixed hedges" in print were sheared hedges with active mixtures of leaf colors producing a calico effect. And hedges usually are linear. And very closely planted from the start. What you have is more like mixed border planting, with a grouping of this and a grouping of that. In an informal, flowing shape bed these would be drifts. This is why the trees being in a straight line is bothersome, it doesn't jibe with them having been placed in sets of several of each kind. And there is a considerable height differential between the Nootka cypress and the others. A good method is to choose shrubs that you expect to grow about 1 1/2 times as tall as the bed or other defined space they occupy is wide. Much beyond that and plantings can appear too tall. Your Nootka cypresses for instance, in this particular case. In time these will grow as big as the native conifers behind the houses in the last picture anyway. Not just too tall for the bed, but too wide. One I've mentioned that was bought as 'Pendula', planted at the entrance to my place shot right up and was soon hanging out over the street, left behind a stump about 18 in. across when I had it cut down awhile back.