Depending on your light conditions, the first thing that came to mind for me was ornamental grasses. Over the course of 230 feet, you could have some fund matching up some contrasting forms with a variety of large grasses. With that 2 ft border of unkempt space, you'll want something that competes well and will help crowd out the weeds. I'd be tempted to fill in around the grasses with a variety of daylillies for extra summer color. Try some variegated Miscanthus, maybe some Pampas, some Karl Forrester Feather Reed Grass, and Panicum 'Heavy Metal".

Re-reading your post, I'm wondering if the unkept trees you reference put you in a shaded situation, much more difficult challenge. If you're not in full sun, the grasses won't thrive. My favorite shrub for shade is Nandina... might try a mix of domestica and a dwarf like "Firepower". In front, mix in blue hostas for a fun color contrast.

Just a couple of ideas. Try to plant large groups of similar plants, but also work in variation. Also, don't forget to plant a few hundred spring bulbs like daffodils to help create some drama in Spring -- neither the grasses nor Nandina look like much in May.

Finally, I would encourage you to take advantage of the long linear lines of 230 feet... either make the bed edge a laser straight line, or play with disappearing curves from a common view point.

Let us know how it goes, and feel free to provide more information or a picture of your project to generate more specific suggestions.

I'd add a selection of buddleias, as well. They are low-care perennial, come in several sizes (but mostly tall), and will provide color for a great portion of the summer. A variegated weigela would give a nice change of pace in leaf color; it too is low-care and I have found it to be very tolerant of partial shade. In fact, I've found most weigelas to be well-behaved large shrubs and more tolerant of uncomfortable conditions than many shrubs. In the shorter category, I like spirea japonica for sturdy (although fragile-looking) blossoms all summer, and almost any of the dwarf arbovitae - take the time to be sure your variety doesn't have to be pruned to maintain size and shape, many don't.

230' is a pretty good distance. Unless you have lots of energy for prepping and lots of $$ for buying plants, divide that length into sections and design/plant one section at a time. You can then repeat the elements you like in the next section. Also consider that many shrubs are fairly easy to propagate - I'd buy one weigela and then -if I really liked it - layer for another one or two to be used farther down the line. When planning placement, don't forget to think in curves rather than straight lines, and to try to have the bed interesting in all seasons.