And you will be waiting forever to get a pool of shade of much size. That will move with the movement of the sun. Probably nearly all people who ask about shading a hot sitting area with trees need an architectural solution such as an arbor and fencing. For immediate, lower budget relief there is patio umbrellas. Another thing about shade from a newly planted tree (in addition to the fact that it might take 10 years or more to get big enough to do even part of the job) is that the shadow will always be a broken one, with patches of sun that poke through, and one that moves in breezes or wind. So if you are trying to look at something while sitting beneath the tree, or would otherwise be unsettled by a shadow that is not continuous or dances around then anything less than a quite big, long-established (existing) tree is not going to work anyway. Otherwise, the maple will be as slow as the magnolia, and the hollies aren't any more likely to damage properly constructing foundations than most small trees or large shrubs. In general, trees and shrubs that shoot up continue to go on shooting up and become too big for what most people want them for, when trying to hide an eyesore or get quick shade. And the ones that make nice long term features for smaller spaces are slow-growing - much too slow for anyone hoping for immediate relief. This post was edited by bboy on Sun, Jan 19, 14 at 15:16

Hi Brigandine! I am a grad student too so I know the confines of container gardens, moving around and badly situated patios! A few things came to mind based on your restrictions-- first, a dwarf bamboo. Dwarf bamboos live in the shade of bigger bamboos so that might work perfect in your space. That would also get you the Japanese style feel you are looking for. When you said you wanted a tree I was also thinking about a tree fern. Ferns are in many Japanese gardens and a tree fern would give you the height you are looking for. Many can do well in containers, just be cautious of the size and weight before you choose one. These would really thrive in your space. Put it next to a stone lantern and you will get the feel you are going for. I do think some Japanese maples will do alright in the shade, and you can prune them to a small shape, but I have no direct experience with them. Good luck!

Since you are doing an Asian theme the groundcover Sanicula caerulescens comes to mind, as it is a native to China. These little plants only grow about six inches tall and spread twelve inches; in your zone these plants may stay evergreen. The paintbrush blue flowers are beautiful on top of the bronze finished foliage. They are hard to find though; I know Streambank Gardens has them. Other Asia native plants that love shade are corydalis,polystichum(evergreen fern), and Athyrium niponicum(Japanese Painted Fern).

Well I am in the process of doing a japanese garden and live in zone 9 near the water. The tree in my avatar is a pine that fits right in. I would say get some white/black japanese pines, some extra japanese maples like the weeping tukeyama and common blood good, a very large Oriental pot with some black bamboo, lemongrass, use the pines as large in ground bonsai because of your height restrictions, trim to 8-10 foot and cut out the central leader pretty much every year for the first 10 years or so "what I am in the process of doing". I also have plans to make a stepping stone water garden with asiatic lillies, edlible water cress and black elephant ear, japanese Iris, and using stepping stones with crevies underneath for a small 1,000ish gallon pond for crawfish so I can have 200 or so crawfish at any given time and that would be nice along with fresh catfish/flounder. Not enough for long term but sustainable. If you have an area like me BLASTED by sun why not do like I am and get a rake and some sand "sand here is free" and some larger stones along with a pagoda or a central sitting rock or bench and rake the sand. Water, coupled with the sand, etc and you coudl probably do one for 800$ if you planed it out right and it would look like a 30k garden ;), mine is 20 x 150ish and behind it on city property that is overgrown I am putting in a weeping willow, black bamboo, a jacaranda tree, and probably some black/white pines. Oh I also put in a ginko, black cherry, and shantung fire dragon maple "best tree for your area hands down but tall :/"... also what tend to look really good and worth considering it sounds like your area gets a lot of sun and is protected would be using a couple of sago palms or possibly banana if you can get the right growth. Tropicana black is also a good option as a backdrop or focal point but leads to more of a tropical look. I am trying to transition a midnight rosary black and white pool garden to a Japanese garden to an Italian garden without making it overly distinct and its working out. Its a 50 year plan and I'll be dead before I finish "I am 35" but hey if nobody plants that live oak :)... stunning will be an understatement in 40 years. Oh another thing, try and include edibles. Why not do a small cabbage row, carrots, traditional Chinese Japanese cuisine like bok choy, you could even plant these in containers that are oriental themed. I reiterate pots because North Texas has some really good deals on very large glazed pottery and concrete pottery "I have about 1k worth of from the Longview Area myself and its high quality and very, very heavy". Everything I have mentioned requires low maintenance for your area or is edible. I have done years of research and what works/wont work. Another idea would be a camelia like black magic trained in a bonsai style of your choice yet in ground as a focal point. Feel free to contact me with any questions :)