Botanically, they're spiraea; the common name is spelled Spirea without the extra 'a' -- Bridal Wreath Spirea.
Starting with the summer spiraeas, which caused me to think of this post, is Spiraea japonica and its hybrids, Spiraea x bulmalda. All are low summer bloomers with pink flowers. 'Goldmound' 'Goldflame'
'Limemound' 'Anthony Waterer' and 'Coccinea' are a few familiar names. I pruned my S. bulmaldas, nameless cuttings given me some years ago, and stuck a few pieces to see if they would root this time of year.
Now to the spring bloomers which were here before I came here:
S. prunifolia -- 'Bridal Wreath' double flowers like little white roses, dark green leaves turn yellow or reddish brown in fall
S. thunbergii -- 'Baby's Breath' a smaller shrub with single white flowers all along bare branches in early spring. Leaves are blue-green and rounder, turning reddish in fall.
S. vanhouttei -- single blooms on clusters on arching brances. Dark green foliage, yellow in fall.
There are perhaps 80-100 cultivars of Spiraea, these are the ones I grow. They are most spectacular if pulled up with the tractor and divided and planted as a long hedge, perhaps with azaleas for the few days of spring fairyland these shrubs provide.
I am taking longer looks as less popular shrubs like philadelphus (Mock Orange) which follows dogwoods and puts on a more lengthy show, blooming for weeks instead of days following the azalea/dogwood display.