You can shape your Blushing Bride and promote lateral growth by pruning, if you don't mind sacrificing some height. When you do so, be sure to cut your stems just above a pair of leaves (or any other node). This will encourage the plant to sprout multiple stems at the point of the cut. Macrophyllas should be pruned just after they finish blooming. In time, your shrub will take on a more mounded, and less leggy shape. If you are counting on your Blushing Bride to rebloom this year, then you can forgo a hard prune until after the second flush of blooms later in the season. Others may have some less invasive ideas- but pruning is definitely effective. Sorry if you already knew all or any of this, and good luck!

You may also want to add a balanced fertilizer to promote foliage and root growth, as well as flower production.
For potted Hydrangeas, I sometimes use a water soluble type formulated for Tomatoes, mixed at the recommended rate of 1 Tbsp per gallon of water and applied every 7-10 days.
In my Zone 7, none is applied after Labor Day, so that new foliage can harden-off before frost. Next years flower buds should also have been formed and hardened-off before frost.
Be sure the soil is moist, before adding any type of fertilizer, to avoid root damage.

I have 2 BB's, well, really CB's (Cyanotic Bride), since they are grown in acidic soil, the blooms are tinted blue, instead of pink. If I can find room for another potted Hydrangea, I would consider adding another BB, so that I can have a certified pink one!

Don't forget, if and when you prune, if you do it in June, July, or August, you can root new plants from your clippings, they root readily and then you can plant several cuttings together and have more plants!!! I've
actually rooted cuttings as late as September but, then you have to be concerned about winter protection such as a cold frame, as they don't have ample time to form a good root ball. Last year I planted two Tovelits in large pots next to my door and they ended up very sticky but in the ground they went in early fall and this year they are coming up very thick and full of buds. Sometimes some of the larger varieties might not do so well in pots. Even though I do think Tovelit might be a smaller variety. Blushing Bride is definitely a large plant eventually. Good Luck, I;m sure another year the plant will thicken out beautifully for you.
Donna

Thank you all for your suggestions! My Blushing Bride hydrangea has continued to grow over the past few seasons and is doing really well. We are considering replacing the shrubs in our front beds with them, in fact, because they are absolutely gorgeous!

ladydancing, me too. Thanks for this post.
Pat