Stems: reddish-brown. Leaves: ovate to elliptic, serrulate at the apex, entire below, narrowed to a very short petiole. Flowers: small in dense leafy-bracted corymbs terminating the branches. Fruit: five carpels distinct, not inflated, seeds small linear with thin membranaceous testa.
The reddish-brown stems of this Spiraea, which are extremely brittle, shed their thin bark annually. The elliptical leaves are dark green on both sides, minutely toothed at the apex and even-margined towards the base which is narrowed into a short stalk. The tiny rose-red flowers are closely crowded in roundish leafy-bracted flat-topped clusters at the ends of the many branches.