How about one of the native deciduous azaleas? The evergreen Rhododendron Cadis also is reputed to be sun tolerant. Mine looks good under similar conditions as you described, but is too small to bloom. Here is a link that might be useful: ARS description of Cadis

Citrus is a shrub turned tree so pruning BYO style on mature trees is not a problem though I would not do the initial topping cut. In my limited experience they may not like high density planting space however. Citrus handles sun quite well once they have a reasonable canopy (usually before second summer) depending upon if you get them in the ground in Oct. As for varieties, do you eat enough lemons and limes to bother having trees that take up your limited space? Usually the answer is to buy lemons and limes at the store (whose quality is actually high) and plant oranges, mandarins and grapefruit you will eat a lot of. Further limes and to a somewhat lesser extent lemons are VERY sensitive to frost damage, so you will work your butt off keeping them alive and productive over their lifetime. That said if you want a lemon select an Improved Meyer lemon as it is the second most frost hardy citrus there is and will not need protecting. It produces a good "lemon" too. I am afraid for lime I'd go with either a thornless Mexican Key lime or Bearss (aka Persian or Tahitian) lime. MK is the king of the limes as far as flavor and Bearss large, pretty, tasty (my second favorite) and precocious. Lemons and limes tend to be year round producers/hangers on trees. A Rangpur "lime" tree is fairly frost hardy. As for standard citrus types: Consider parent navel Washington, Cara Cara, Arizona sweet, Marrs or Trovita orange, Daisy Mandarin (Tangerine), Rio Red or Marsh grapefruit. Also Midnight or Delta Valencia orange. This will provide you with (fairly seedless) citrus from Nov through the end of May. These are not too frost sensitive. I prefer Seville Sour Orange rootstock for all. I believe that narrow 5 foot wide strip mostly in the shade will not be productive for any fruit. But if you paint the area block walls white (reflective sunlight) and plant kumquats (I like Meiwa's; sweet and few seeds) you might get away with it. Kumquats are the most frost hardy citrus and naturally small trees---still require pruning to keep them that way. They are normally year round fruiters but if they don't get enough sun may be seasonal. You could include a limequat as a lime substitute as it is frost hardy as well. Consider turning them into a hedge. Citrus is a bush. It normally should be grown up and then the canopy allowed to grow down shading the sun sensitive trunk. Kind of a mushroom shape. The best fruit will be found in the first 8 feet of canopy (tree height) so just over that is a good target height for what you want to do. Paint any exposed trunk and main branches white with water based white latex paint (50%). LIGHT pruning is best done in late June (oh joy) with the sun directly overhead to achieve a slight dappled pattern of sun filtering through and hitting the ground. With only 20 feet you really should only plant three trees. You can certainly try to squeeze in more but I am not optimistic as to fruit yield and how happy you'd be. Here is a link that might be useful: 2011 Maricopa County Citrus and Deciduous Fruit Guide

Hoovb, thank you for your suggestion. I completely forgot I asked this question, and found it while searching again. :-/ Here's a photo of the area, taken May 2011. The blank slate I want to design is about 9x9', in the corner between the tree trunks. The roses in the foreground are separated by several feet. A compost pile had been there for a few years so the soil has a nice top layer of compost. I'm considering a few possibilities: - One large Hybrid Musk rose (Darlow's Enigma - I've grown it before in a smaller spot and had to give it away - it loved the shade. - Flagstones surrounded by smaller plants, leading to a bench in the corner. This corner is not highly visible from the patio or house, but it is the view from our bedroom window and we'd like it to look nice.

It needs 8 hours of sun during the growing season. Winter exposure is irrelevant. The perennials forum would have been a more appropriate place for this question.