The Mid-Atlantic region may be in full Azaleamania right now but let's not forget what I'll modestly call the Queen of Shrubs, the glorious doublefile viburnum. I was practically forced to buy these plants back in '86 when I used the free services of a nursery's landscape department to create a border between the lawn and the woods; it was February and these guys looked totally unpromising. But the designer swore by them and I took the leap into unknown plant territory, along with several more of my now-favorites.
I know the questions are coming, so I'll hurry to tell you everything I know about them. They're almost as tall as dogwoods - about 15-18 feet, and bloom at the same time, always white and always in this lovely horizontally reaching form. Besides watering in newcomers during their first season, the only maintenance required - and it really is required - is annual pruning. After the blooms fade is the perfect time to remove any stems that cross and crowd others, and most importantly, remove completely one to three of the oldest stems to the ground. As counterintuitive as this may seem, and I've discovered that lots of good pruning practices are just that, it's the only way to keep the whole plant from becoming top-heavy and increasingly less lovely.
The bottom photo shows, on the right, another doublefile viburnum, or V. opulus V. plicatum tomentosum 'Shasta' for the Latin-inclined. On the left is a V. macrocephalem or snowball-type that's not my favorite. Snowballs, mopheads (in hydrangeas) and pom-poms of all types are, I dare suggest, kinda outdated, but go ahead and disabuse me of that notion, pom-pom lovers, because I know you're out there. My biggest complaint about it is the tendency for the large flowers to seriously weigh the branches down - not pretty - and my notes on this plant tell me that Henry Dirr - a god in the world of plant experts - recommends hacking it down to 2 or 3 feet every year, which probably solves the problem. As always, Henry knows his woodies.
A final thought about these photos, especially the top one. It illustrates a point I've been known to harp on - that borders look best when the plants are layered, from large trees to understory trees to shrubs, to perennials, to groundcover. Not only does it create enclosure and privacy, and therefore create a garden, but it mimics nature's own design for forests transitioning into meadows, the prototype for our borders-around-lawn. Interestingly, we humans seem to respond most to nature's own design, even when it's a helluva lot of work to create it. It's one of many reasons that naturalistic design is so popular and, I venture to predict, will stay that way.
Here's more, after reading my very first comment: Damn, I still didn't say enough. Excellent question, about when to start removing older stems. First, I've seen lots of these shrubs in nurseries with really crowded stems and in need of a good thinning out, so start there if you have a young one. That'll give it a better structure to grow on, and the removal of old stems probably won't be necessary for the first few years. Then the first time you get one of those awkward, too-tall stems, remove it completely.
And just one more thing about pruning. If you happen to have any old, overgrown and top-heavy viburnum of any type, I'd recommend a severe hacking back of all the stems, to the base or close to it. I did this to the pom-pom viburnum and it came roaring back with renewed vigor and a much better shape, and reached 2/3 of its original height in one season. Pruning by Peter McCoy - my Bible on the subject - gave me the courage to try it and it worked.