Emerging in April, the flowers are borne in rounded clusters at the end of branches. They are about 1 cm (just under 1/2") across, greenish-yellow, with 5 petals and 5 sepals. Cloaking the tree in green, the flowers give the appearance that the tree is fully in leaf. Norway Maple trees in full flower look like they are covered in yellow/green pom-poms. This maple tree species is variously reported as monoecious, i.e., producing unisexual flower with both sexes on the same tree, or dioecious (separate male and female individuals).