Great idea, Sully! I don't have that one yet, and I love purple anything. It would look very nice with the Limelight, and will add just the color and contrast I'm looking for.

Thanks again! : )

There are a lot of Columbines that have purple tones. My favorite is the Blue and White "Winky" -- it's gotten very big and gets on quite nicely as neighbors with my roses.

Gaelic, I love columbines, and I definitely plan to get some more. However, I really wanted something larger for this spot. I went ahead and bought a Ninebark this a.m. as Sully suggested, and if it doesn't rain real soon, I may be able to get outside and plant it.

If you bought Physocarpus 'Diabolo', that have a very deep burgundy/purplish foliage in full sun, it may not work as planned in your part-sun/part-shade situation.
It really need a FULL sun to achieve that color that you see on a pictures.
You are correct that Limelight need a some sort of contrasting color companion(s). It look absolutely stunning against dark or blue evergreen backdrop (Colorado blue spruce would be ideal choice in that respect).
If grown side by side, I'd chose either 'Diabolo' ninebark or 'Royal Purple' smokebush, but both need a full sun to show the best. The only part-sun lovers with a dark purple-burgundy foliage I could think of would be a numerous cultivars of Japanese maples, that also could provide a nice foliage texture contrast.

Thanks for pointing that out about the sun. I was afraid that that may be the case and planted it a little further out so that it would get more sun than shade. If it doesn't work, I'll have to move it. I also have dark green arborvitaes as a backdrop so maybe the Diablo is not even really needed there.

Thanks again.

I just purchased the limelights for under my front window. I planted them with Autum Joy Sedum, Boxwoods, Bucktornes, and the variated hostas with the purple shoots. It looks great(So far).

I have that ninebark and just wanted to add that it is the toughest shrub I've ever planted! It was in a hot, dry, south-facing perennial bed that the chickens decided to take dust baths in. For a couple of years, until I decided to give up on the idea of free range chickens, and while I had small babies and couldn't really pay much attention to the garden, the chickens killed everything else in the bed, and the roots of this shrub were exposed. It lived and grew through all of that. The chickens are now contained in a fenced yard, and the ninebark is still doing great, surrounded by new plantings.