It will replace the Flowering Almond standard that you see in the photo. Given its important location it needs to be an extra interesting specimen ;). What might you suggest?
edit by @Daniel Mosquin -- the post below was made before it was clarified that the original post was specifically requesting a dwarf maple. Poncirus trifoliata contorta, Flying Dragon Bitter Orange. Slow growing with striking appearance of curved branches and large thorns, and small orange inedible fruits (in the distant future). Caragana arboresciens 'Pendula' , Weeping Siberian Peashrub, graceful foliage with small yellow flowers. Syringa meyeri 'Palibin', Korean Lilac, several other named varieties including 'Miss Kim', in various colors, all fragrant, with attractive foliage. Witch Hazel comes in a wide variety of colors. Rhododendron yedoensis, Korean Azalea, can be trained to grow upright as a column of a few upright branches. Stewartia pseudocamellia Japanese Flowering (false) Camellia, mid-summer white flowers. Magnolia stellata, Royal Star Magnolia. Carpinus coreana, Korean Hornbeam doesn't have conspicuous blooms, but has lovely foliage, but is hard to find. All of these are smaller trees, but you have to do your part, too, to keep them small. I see by your photo that you have allowed your Flowering Almond to get out of hand. Anyhow, you are pretty far north, so any tree that flowers and matures seed does so at a disadvantage because your season is too short to both mature seed and set flower buds for the next year, resulting in a pattern of flowering well every-other year. You can short-cut that process by immediately cutting off all spent flowers/seed-heads so the tree can skip to the next part of the cycle right away: growing next year's flower buds. Also, You need to "steal" the ability of the tree to grow as much or as big as it would unimpeded, so also immediately after blooming, you need to reduce the branches by ~half~. It's taken me hours and hours to carefully depict how your tree should look after your prune it every year. Thank God for computers! (I didn't have to break out the Crayolas.) Early in the tree's life you need to choose an architecture, that is the main branching structure. You need to save the heaviest branches in strategic locations as pictured. They should radiate out from the trunk like a spiral staircase as viewed from above. Ideally, each ascending branch rotated ~130° and about a foot higher along the trunk. This maximizes light getting to lower branches. This sounds more difficult than it really is and doesn't have to be exact to look just fine. The branches you choose will only protrude half way to the edge of the brick border on the ground. That will give you just enough room for new growth from the main branches each year. No twigs can grow straight down; nothing can grow out beyond the imaginary red canopy line. When it does, you trim it back ~half way~ or off at its origin. Leave no stubs, but don't gouge the mother branch either. Cut branches and twigs off flush. Branches will grow approximately straight from the tips. When you see that a branch is pointed where you don't want it to go, you remove it, or trim it back to a bud or twig growing in an acceptable direction. No branches are allowed to grow towards the interior, or crossing another. In all cases you are keeping it smaller by removing anything growing in the wrong direction or too congested. You are making space. Empty space between branches. Ideally, you will have flat fans of twigs and foliage growing sideways from the main branches, plus some growing up from the mains, but you maintain space between branches by not allowing anything growing down from the bottom of a main and nothing growing up that interferes with the branch above. To stop or slow down linear growth, trim the bud on the tip of the branch and growth will be encouraged from buds on that branch closer to the trunk. Leave the tip bud on to encourage more growth from the end and less from buds on that branch closer to the trunk. Over time, the tree will get a little taller each year. You will intentionally chose how tall. If you keep it short enough to prune it from your standing on the ground position, it will be easier to keep it in-bounds for years and years. You will also choose to cut off older main branches in favor of new, smaller replacements every few years to keep everything in scale. You don't want to have a big blank spot in the design when you do that, so look ahead, and nurture a replacement for a couple years in a good location to be a replacement for the one that's getting too big. And that's all there is to it!
And that's all there is to it! Hardly! What an incredible reply. I have my heart set on a JMaple for this location but @Michigander your incredibly detailed reply has got me thinking of other possibilities. Thank you so much for taking the time to respond.
The above first Link is to Mr. Maple where many varieties are listed. Keep in mind that all white parts of a leaf are parasites because they live at the expense of the chlorophyll bearing leaves. Clear green and red are 100% productive, while chartreuse is ~60 to 75% productive, yellow is ~40 to 50% productive, and all lighter colored portions are parasitic to a greater or lesser extent all the way to 100%. Pretty, but useless. Many JM cultivars are sold to the public based upon color (a wild understatement). Often, that is spring color that evolves to all green, and/or an autumn color which evolves from an entirely green summer leaf. In both cases, none of the leaf is parasitic. Lots of cultivars evolve from a spectacular variegated leaf in spring to all green more slowly, or not at all. You need to know exactly what you are buying because: The ultimate size of the tree, and the speed of growth is directly related to the percentage of green or dark red/purple in the leaf. Since you want a smaller tree, you want a tree that has slower growth and smaller ultimate size. Any tree will be smaller than the type by the same percentage as the amount of unproductive foliage it has. But there is a mixed metaphor here: you want a full sun JM. The darker the green or red, the better defense against sun a tree will have, so it will also be bigger. The lighter colors will get brown/sunburned edges sooner, and the edges of deeply cut foliage will, too. I can only offer three candidates because that's all I have direct experience with that you might like: Acer palmatum 'Summer Gold' is new so I can't speak directly to how big it will get, but it's yellow so that means ~50%, or so, may not be available on a standard which would be less desirable than grafted at the soil line so that you can have lower starting branches. A. p. 'Bene Hime' has a very small red leaf all year. Finding one grafted on a higher standard may be problematic, but is do-able if you are persistent. A. shishiwaranum is the Lionshead. Very small green leaves , they will grow to 7 or 8 feet, but it will take forever. A good candidate that should only be trimmed in May or June to avoid dieback of trimmed branches. You may be able to get away with almost no trimming for many years because it grows so slow. Finding a big one may be difficult. Good Luck hunting!
