Pink spiraea, a close relative of baby's breath, is an easy-to-grow shrub with delicate blooms that appear throughout the summer and fall. There are two varieties of spiraea that produce pink blooms: Japanese spiraea and bulmata spiraea. Both varieties spread quickly and are considered invasive plants because they can nudge out other desired growth in your flower beds or garden. For this reason, regular pruning of pink spiraea is a necessity that is fortunately easy to do.
Fill a bucket with water, then add a few capfuls of bleach to create a sanitising solution for your pruning shears. If your shears come into contact with an infected branch, it is easy to spread this infection to the rest of the shrub. Therefore, you should dip your shears in the bleach solution to sanitise them before making every cut.
Cut each of the spiraea branches to about 6 inches above the ground with your pruning shears in winter or early spring. This is called renovation pruning. Although it seems drastic, rest assured that your spiraea will re-emerge quickly. Spiraea is an extremely hardy cultivar and difficult to harm. In this type of pruning, it is not necessary to angle the cuts.
Snip fading blooms with your pruning shears in the summer and fall at a 45-degree angle just above a bud or offshoot. This encourages a second bloom to grow in the same spot, intensifying and extending the pink spiraea's blooming season.
If your pink spiraea spreads into unwanted territory, you can mow over it or cut it to the ground; this may, however, be repeatedly necessary.