How/when do I cut back overgrown out of control Bridal Wreath bush?

http://homeguides.sfgate.com/bridal-wreath-spirea-pruning-90101.html

http://homeguides.sfgate.com/care-bridal-wreath-bushes-95423.html

Hello Lynn! I have one and if you don't care about getting a full bloom in spring, you can prune it back right now. The new flowers come on the old wood. It will grow back, but the new growth won't flower in the spring. For a full bloom, prune it as the flowers die. How big and old is it. Put gloves on and cut 1/3 of the oldest branches off close to the ground.

After the blooms have faded, you can prune the spirea to a more manageable size. The spring pruning should be a set of strategic cuts made to reduce the size of the plant. To keep the natural appearance of the shrub, follow the stem you want to remove, back to the point of origin off the main trunk. Make the cut as close to the main trunk as possible. If you just lop off the top of the shrub, the cut stems will send out new growth shoots that may intertwine with each other and cause damage to the shrub.