There's no reason you can't plant the same thing along the entire length if the look you want is a hedge, rather than a shrub border. A formal hedge would be shrubs that are trimmed, possibly evergreens. An informal hedge would be created with plants that have a pleasing natural shape, and they would be allowed to grow naturally, or with a snip here and there to maintain a neat shape or control size. It can be all the same kind of shrub, or a mix of evergreen and deciduous shrubs that would either bloom at different times, or provide year round foliage color, or interesting seasonal changes. It all depends on what look you're after. The style of your house and surrounding neighborhood might suggest which look would be right, or you can just go with your personal preference. I would see if your library has books on shrubs, maybe check out the shrub forum, and search the web for articles and information on hedges or shrub borders.

I have the same situation, split rail w/ wire fencing on 2 sides of the back yard (record north is right at the corner), w/ the neighbors' privacy fence to the s/w side & the house & side fences along the s/e. I have alot of large maples, oak, beech, pine in my yard & also large trees in the park to the n/w & my other neighbors' yard n/e. What has been successful so far-at the back, which borders the park & has 5 white pines, limbed up, & a maple (basically a western exposure, but some huge oaks & cedar at the park providing additional shade) I've planted nandina, pieris japonica, viburnam, J. maples-Scolopendrifolium, Spring Delight, Garnet, & Viridis in the N. corner. I also have hydrangeas-oakleaf, Nikko, Lady in Red, blueberries, itea, fargesia robusta, & camellias. The soil under the pines is rock hard clay, dry & shaded. I try to keep the newly planted things watered, but we had a brutally hot summer. What didn't make it-a Japanese black pine, a camellia that was attacked by a squirrel. I planted lots of heucheras around the Jmaples, I hope some will return next spring. I tried hops along the fence, but they didn't make it (I think I planted too late), but I hope the passionflower that was vigorous last year will return. On the n/e side which borders my neighbors yard, which is lovely, but mostly large old trees, lawn, & ivy, under the shade of an enormous maple-which has terrible soil, it's clay, dry, rocky-I've tried alot of shady perennials. I'm adding compost to the bed as fast as I can make it. Right now, it's mostly variegated & plain J.pachysandra, epimediums, hostas, hellebores, violets, rohdea japonica, a variegated sambucus (I had 2, 1 died), heucheras, & a gorgeous 'Snow Flurry' camellia. My experience so far, (I've been here 2.5 years)is that it's challenging but possible to garden in less than ideal conditions, & my garden gives me a great deal of pleasure...

Thanks for the kind comments, Marie! Here are a few photos, splaker. I hope that this helps you with your project. Before I started this project in fall 2009, I think, I tried to web search mixed shrub borders and didn't find much that inspired me. But I knew I had seen in person similar things planted various places, so I had some ideas in mind and then just winged it. My goals were to block or distract from some of the sightlines to a work area from the main entrance drive. We had just cleared a wooded area to have more sun, so I was starting from a blank slate. I knew I wanted a mix of evergreens (for winter interest) and deciduous shrubs, vines and perennials for colorful and contrasting foliage and flowers. I know I have more space than the typical suburban yard, but something similar to this could be done on a scaled down basis. June of 2010 after planting fall 2009. 3 kinds of evergreens (2 or 3 of each randomly spread down the bed length - Thuja 'Sunkist', Thuja 'Techny' and a slower growing cultivar of blue spruce that I will probably eventually have to remove due to large size or budworm damage), a few small pagoda dogwoods, a couple of Hydrangea paniculata (Quickfire and Pinky Winky), a Coppertina Ninebark, two Spicebush (Lindera benzoin), a few rhodies, some winterberry holly, and a few perennials. Before planting, I laid down a bunch of composted manure. After planting the various shrubs, I mulched heavily for moisture and weed control, first putting down cardboard and then about 6" of loose mulch that packed down to 4" or so. Perennials were planted around the edges after the main shrubs were in by cutting through the cardboard. I tried to leave enough room between the evergreens and shrubs to allow them to grow to just grow together overtime, but not be super crowded, so it was rather sparse the first year or two. I didn't do formal plans, but knew the ballpark size of the mature shrubs and the bed size, and once I bought the plants, I plopped them down in the bed and moved them around until I liked the layout, and then got out the shovel. I didn't pick out specific varieties ahead of time, but went around to local nurseries during fall sales knowing that I wanted rhodies, varied colored medium evergreens, etc. and chose from what they had available (that met my needs) to keep expenses down. Looking east from the middle Looking NE from the SW side (June 2010) In December of 2010 after one full growing season looking west from the dirt pile just visible on the right (east) side of the photo above After 4 growing seasons with some added perennials but not much in the way of added shrubs it is fairly full. Late October 2013 June 2014 looking East along the front of the bed. Looking down the back side as fall color is just beginning to develop - no perennials since this is the work area side. Here's a photo in taken late November 2014 that was from a similar angle to the second photo at the top. There have been a few plants over the years that haven't worked out due mostly to the voles that are a curse of my gardening existence, but for the most part I am quite happy with the bed. It's at my husband's shop so I don't get down to it as regularly as I might wish, but it doesn't need more than a few of hours of weeding per season and some tidying up and cutting back in the fall as long as I keep the mulch in good shape. I add more mulch every couple of years where there is space between plants. I've also added edging, a combination of the rolled edge black plastic edging from a big box store and recycled bricks lining the inside edge of the plastic (visible 2 and 3 photos up) to run the lawn mower wheels on so no edge whacking needed. Also, a couple of comments on some plants mentioned in previous comments. I have 3 Viburnum plicatums, one of which is about as old as the bed above and might be mariesiii but might be another selection. They bloom well every year (we got to -22 last winter and near that most winters) so you should be OK unless you get a whole lot colder than that. They all have great fall color. Burning bushes can seed around to wild areas, so I wouldn't recommend them for that reason, but they are also boring green blobs most of the year. Blueberries are a good replacement if you have acid soil with spring flowers, summer berries for you or the birds, and nice red to maroon autumn color. I ripped out my one Viburnum 'Blue Muffin' because it didn't bloom well, had no fall color in my garden, and was infested with Viburnum beetle. There are quite a number of medium sized/slower growing Thuja cultivars that won't get giant (as well as other conifers that you could check out on the conifer forum.) I found 3 Thuja types in good sizes in local nurseries in my quite rural area, so you have a good chance of finding some. If you have a lot of deer they may not be a good choice unless you want to spray them in winter. We have deer, but are rural enough that they don't bother the gardens for the most part. I really like the various variegated shrub dogwoods and the size of the larger ones will work well for you. Coppertina is has been a great shrub for me, but if they are prone to mildew in your area, there are others that are less mildew prone in tests. I'd love to hear how your project works out!

What a shame you have to give up 15 feet, but nice way you've decided to use it! First of all, to me that image looks like it's been cut-and-pasted together. I don't know where it is, but here in my zone 7, some of those things just wouldn't be blooming at the same time. And you certainly cannot expect to have perennials blooming all season long ... even a short one ... as they tend to bloom for only 4-6 weeks before going into a resting phase. You could do something like that with annuals, since they bloom all season long, but, of course, you'd have to replant every spring. When I was a child, our neighbor had an annual garden like that - snapadragons, zinnias, sunflowers, celosia, alyssum, and I can't remember what else, rioting along the back wall of their home. It was glorious. So that it doesn't look forlorn in the "off" seasons, you might consider a mixed shrub and perennial border, with some bulbs thrown in for good measure. Choose some great shrubs for the "bones" to give structure and interest to the border year 'round. Then start adding perennials and hardy bulbs, selecting them to give a succession of bloom from early spring through late fall. Be sure to consider leaf color and texture, as these will give interest to your garden even when not in flower, and can complement and highlight the ones that are in flower. Having lived in zone 7 all my life, I hesitate to make any suggestions for your zone, but would suggest there are numerous books and websites that can help, and the most helpful might be a visit to a local public garden to see what performs well and plays well together. Of course, taller plants in back, shorter ones toward the front, but try for lines that undulate in height and from front to back to avoid a stair-step look. FWIW, one of my borders, in half sun, has blooms from February through November with snowdrops (galanthus), daffodils, grape hyacinth, tulips, creeping phlox, perennial candytuft (ibiris sempervirens), tradescantia (which is wearing out its welcome with its spreading habit), peonies, irises, baptisia, roses, hardy geranium, cultivated daylilies (not hemerocallis fulva, the invasive orange "ditch lily"), false aster (kalimeris) 'Genghis Khan', garden phlox ('Davidii' and 'Franz Schubert', fairly resistant to powdery mildew), threadleaf coreopsis (either 'Zagreb' or 'Moonbeam' ... can't remember), nepeta, bee balm (monarda), obediant plant (physostegia) 'Miss Manners' (she reseeds less prolifically), New England aster 'Raydon's Favorite', Montauk daisy. There's a blue rug juniper for winter interest, two different flowering weigelas ('Wine & Roses' and 'Rubidor'), and at one end a mature redbud (cercis canadensis), at the other a passionflower vine (native passiflora incarnata) climbing the lamp post. Probably have left someone out ... sorry, guys. I will confess to also having a variegated euonymus (alien invasive ... days are numbered), just removed a Japanese spirea (another A.I., and it's neighbors responded with wonderful growth this spring), and a few years ago removed a red-leaf Japanese barberry (another A.I.). Where it wraps around into shade, the bed transitions into to shade plants ... but that's not what you need. That border did not happen all at once; it evolved over the years and, as you can tell, is still evolving ... Well, that's the whole point of gardening, isn't it? After all, I've heard it's been called the slowest of the performing arts.