Although seldom as flamboyant as fruit tree blooms, deciduous trees also bloom to produce seed for new trees. Some trees produce seed-protecting nuts and some give their seeds wings of fluff or substance. The two-seeded samara of the maple (Acer spp.), called “helicopters” by generations of children, begins mid-summer, but the maple’s flowers that bloom in early spring are not nearly as showy.
Maples are a widely varied family of trees, shrubs and even vines that grow in areas from U.S. Department of Agriculture plant hardiness zones 2 to 10, depending on variety. Boxelder (Acer negundo), for example, is widely considered a weed tree that grows in USDA zones 2 through 10. The sugar maple (Acer saccharum) grows from USDA zones 3 through 8. Shrubby, colorful Japanese maple (Acer palmatum) thrives from USDA zones 5 through 8; and the maple vine (Acer circinatum) from USDA zones 6 through 9. Red (Acer rubrum), silver (Acer saccharum) and Norway (Acer plantanoides) maples are planted widely in urban areas to USDA zone 3. Hybridization has taken the best qualities of each. Red and silver maples are hardy to USDA zone 9, but Norway maple has less heat tolerance and is hardy to USDA zone 8. Each maple blooms as early as it can tolerate in its zone.
Maple flowers bloom in clusters called racemes. Flowers form -- and may continue to form -- while samaras develop, depending on maple variety. Maple flowers are imperfect, meaning that each flower lacks one sex organ. Dioecious maples may be either male or female. Boxelder, for example, grows insignificant flowers on both male and female trees trees, but only female flowers give way to fruit. Unisexual trees, such as silver maple, have both male and female flowers on the same tree. Many maple varieties bear green, yellow or greenish-yellow flowers. Some are showy, like the red blooms of red maple and its hybrids.
Occasionally a late freeze will nip spring-flowering plants, but trees seem to have a sense of timing that protects them from cold. Maple flowers precede the tree’s leaves and often persist throughout samara formation, producing reserve flowers in case late frost nips early fruit formation. In Florida, red maples might bloom in December or January, but further north, they might bloom in March or April. In another plant adaptation example, maples will continue to bloom after samara begin to form, a habit that protects against late freezes and hungry critters that might snatch tender seeds.
Depending on variety and weather, flowers might persist for a month or two. When a sudden warm spell strikes and spring becomes summer overnight, trees leaf out sooner and samara production speeds up, so bloom period may only last for three or four weeks. The timing of maple’s flowering might differ from year to year, but when flowering, no matter how long it lasts, is successful, you’ll have plenty of helicopters to mow or mulch.
- Clemson Cooperative Extension: Maple
- Missouri Botanical Garden: Acer Negundo
- Missouri Botanical Garden: Acer Saccharum
- Missouri Botanical Garden: Acer Palmatum
- Washington State University Extension: Vine Maple
- Missouri Botanical Garden: Acer Rubrum
- Missouri Botanical Garden: Acer Saccharinum
- Missouri Botanical Garden: Acer Platanoides
- University of Florida IFAS Extension: Acer Rubrum: Acer Rubrum
- Lady Bird Johnson Wildflower Center: Maple
- Photo Credit Jupiterimages/Photos.com/Getty Images