The flowers are generally unisexual, with male and female flowers appearing in separate sessile clusters, though they are sometimes also bisexual. They appear in late winter to early spring, from December to May depending on elevation and latitude, usually before the leaves. The tree itself is considered polygamodioecious, meaning some individuals are male, some female, and some monoecious. Under the proper conditions, the tree can sometimes switch from male to female, male to hermaphroditic, and hermaphroditic to female. The red maple will begin blooming when it is about 8 years old, but it significantly varies between tree to tree: some trees may begin flowering when they are 4 years old. The flowers are red with 5 small petals and a 5-lobed calyx, usually at the twig tips. The staminate flowers are sessile. The pistillate flowers are borne on pedicels that grow out while the flowers are blooming, so that eventually the flowers are in a hanging cluster with stems long. The petals are lineal to oblong in shape and are pubescent. The pistillate flowers have one pistil formed from two fused carpels with a glabrous superior ovary and two long styles that protrude beyond the perianth. The staminate flowers contain between 4 and 12 stamens, often with 8.