'October Glory' red maple in East Tennessee

Red maple (Acer rubrum) is commonly planted as a 40-60 feet tall street or shade tree (USDA hardiness zones 3-9). Tiny red flowers burst open early, often in early March throughout the Southern Appalachian region (USDA hardiness zones 6 and 7). Flowers give way to reddish double winged samaras. Its glossy dark green 3-5 lobed leaves are 3-6 inches across and with deep red petioles. Red Maple’s most identifiable trait is its vibrant autumn leaf colors, which can vary by a month or more depending on cultivar.

Red maple is native to moist well drained soils, preferably in full to partial sunlight. It tolerates wet soils and is unswayed by temporary flooding, such as in rain gardens. In some Midwest states it has earned the nickname “swamp maple”. It is resistant to urban air pollutants.

Red maple may be troubled by insect or disease problems, often when tree is planted on a poor landscape site. Leaf aphids, wood borers and scale insects can be occasional pests. Verticillium wilt disease attacks the vascular system, frequently the result of unusually long dry spells lasting three or more years.

Red maple is sometimes called “soft maple” because high winds and ice storms may break branches. Its notoriously shallow root system may raise adjacent sidewalks or driveways. Pruning is best postponed until the spring and summer months when sap pressure in low. Sap from this species can be used to make maple syrup.

Five popular cultivars (rated by fall leaf color date) in the southeast and mid-Atlantic states include:
Autumn Blaze® (A. x freemanii) – 50 ft. x 40 ft. – earliest deep burgundy red leaf color
Red Sunset® (A. rubrum) – 45 ft. x 35 ft. – early bright red leaf color
‘Autumn Flame’ (A. rubrum) – 35 ft. x 15 ft. – better red color in southeast U.S.
‘Armstrong’ (A. rubrum) – 45 ft x 15 ft. – columnar habit for narrow street plantings and variable fall color
October Glory® (A. rubrum) – 40 ft. x 35 ft. – one of the latest for red fall color