Hydrangea macrophylla, commonly called big leaf hydrangea, is a deciduous shrub with a rounded habit that, in the St. Louis area, typically grows 3-6’ tall and as wide unless damaged by harsh winters or pruned smaller. It generally features serrate, obovate to elliptic, dark green leaves (4-8” long) and large clusters of long-blooming summer flowers in either lacecap form (flattened flower clusters of small fertile florets with scattered showy sterile florets often forming a marginal ring) or mophead form (globose flower clusters of mostly showy sterile florets). Genus name comes from the Greek words hydor meaning water and aggeion meaning vessel in reference to the purported resemblance of the seed capsules to small water pitchers. Specific epithet comes from the Greek words makros meaning large and phyllon meaning leaf in reference to plant leaves. Hydrangea macrophylla 'Pia' is a dwarf mophead cultivar that typically grows in a mound to 2' tall by 2' wide and features pink flowers.