H. macrophylla Mme Emile Mouillere would fit the bill for zone 7. Start white and get a hint of pink or blue before fading to green with red speckles.

H. arborescens Annabelle grow to about 4', maybe a little higher, start white and fade to bright green.

Otherwise, you could look at an H. paniculata like Quick Fire that produces white blooms in June that change color (white/peach/pink/red) all the way into fall. Little Lime and Vanilla Strawberry would be other good choices, offering different combinations of green, pink, and white.

All of those could be spaced ~3' apart and easily make a hedge. And in zone 7 you can trim all of those down to about 2-3' each spring and get a nice rebound and bloom.

Oakleafs (H. quercifolia) are winter hardy (Zone 5), all have blooms that start white, fade to a shade{{gwi:807}} of pink and, in the Fall, all have great leaf color changes too. Getting one that stops at 5' may be difficult without pruning to maintain height. But there are some compact ones. Geographic location and sun exposure may keep large shrubs short. Consider some of these 6' or these compact ones:

Alice (panicles turn a dark shade of pink, close to red; foliage turns red/orange/etc) can get 10' in southern locations where the growing season is very long; Snow Queen has more upright panicles, giving it a royal appearance and nice fall leaf colors (about 10' high); on the other end of the scale, Munchkin and Pee Wee get 3' high and the leaves change to reds/oranges in the Fall; Ruby Slippers is slightly bigger (about 4' with darker pink blooms); Snowflake has double awesome blooms and nice fall foliage (about 5-6' high); Harmony has piles and mounds of flowers that do not resemble a panicle (about 6-8' high); Amethyst starts white and fades to nice shades of pink with a 6' height.

All Oakleaf Hydrangeas require well draining soil however, as their roots will develop root rot if allowed to sit in wet soil for long periods of time.

Annabelle and its "cousins" will produce blooms that start green and then turn white. The difference between them is some will have slightly stronger stems than Annabelle. Fall foliage is just so-so.

Mopheads that start white are in the same boat as Annabelle. Choose based on advertised height; fall foliage is so-so too although some supposedly do have nice fall foliage. Lady In Red is advertised to have nice fall colors but it did not here. The leaves just turned yellow (the usual) and dried out. Some whites to consider: Blushing Bride (almost all white), Bridal Bouquet, Peace, Princess Juliana, White Out, Mme. Emile Moulliere and Sister Therese. Note that the center of some of these can look yellowish for a while, not green or greenish.

At this point, you end with some of the paniculatas. They all start with white blooms with various sizes, mostly large. While their tendency to bloom on new wood helps when we have cold winters, fall foliage is not as good as the oakleafs. Compact or dwarf ones: Quick Fire blooms early (6' or more), Little Lime (3' or more), PeeGee (6' or more) and Strawberry Sundae (3-4') are compact. Luis

This post was edited by luis_pr on Mon, May 26, 14 at 9:28

Thank you Springwood and Luis!

Why not mix varieties for your hedge?