The inflorescence of spiraea lucida
is a dense, terminal cluster, around 4 inches in diameter, containing dozens of tiny white flowers, which may have a pinkish tint. Flowers are about 0.2 inches wide, formed of five triangular green sepals, five round white petals and up to 25 white stamens, exserted well above the petals. All flower parts are usually hairless.
Stems are generally unbranched, and relatively tall, growing upwards to a height of around 3 feet. The large, oval, hairless leaves are attached by stalks up to half an inch long. They have a lighter-colored midvein and fainter, pinnate side veins. The upper half of each edge is marked with large and small teeth.