The Big Flowerbed

About 15 years ago, I started a major flowerbed in the backyard.  I started out with roses and annuals, but switched to perennials after a few years.  I had a job, and house to maintain, and other yard areas to clear (it was virgin property - still left semi-natural, but the brambles and scrub saplings were slowly cleared).  I liked the idea of a perennial flowerbed, no replanting every year.  Weeding among them became worse than planting new annuals.

The flowerbed is an "Ell".  60" on the long side and 30" on the short.  The short side is against the back house foundation and faces south.  I get 1/2 to 3/4 sunlight, never full sunlight.  Too many mature neighbor's trees.  There is a 6'x4' pond offset in the long side toward the short side, which makes perfect symmetry impossible.

I still like the idea of mostly perennials, but, quite frankly, they don't bloom much or for long.  And most don't live as long as you would think.  "Perennial" does not mean forever or even 3 years sometimes.  And perennials from the best quality nursery have suddenly become more expensive.

So, I'm concentrating on those that have "lived long and prospered" (apologies to Star Trek), those that are individual plants that don't slowly spread, and those that are individual plants but can be divided.

I'm planning a major redesign of the entire flowerbed.  Essentially, I will dig up every single useful plant, divide those that are happy to be divided, move them around to where they might be happier, and move the more invasive spreading ones (like lysimachia firecracker and cultivated goldenrod) to a new area where they are welcome to spread all they want (because I can mow around the area).

My dilemma is the new flowerbed design.  I can design it with large areas of individual plants for impact (as recommended by some professional gardening magazine designers) or repetitive with smaller clumps of the same plants in several places spaced far apart (as recommended by other professional gardening magazine designers.

I like both ideas, but of course, I can't do both at the same time.  So, the dilemma...

I'm been laying out possibilities of both for days on graph paper (got to do it true to scale or I won't really know what it might look like).  Fortunately, I have a month to keep playing around with both ideas.

Any thoughts?