PSC 2620: Woody Trees and ShrubCourse HomeWeek 6

Acer rubrum - Red Maple

Plant Viewer
Red Maple is a large shade tree that is famous for its fall color. In the fall, the leaves turns an extremely bright red.
New leaves emerge with red overtones before they fade to a dark green. The flowers on Red Maple are somewhat ornamental, especially when the tree is viewed from a distance.

Plant Description

Acer rubrum is a popular deciduous shade tree that is cold hardy and fast growing; and famously has bright red fall color. Do not be mistaken by the common name of Red Maple and take it to mean that the leaf is red. In fact, the most popular red-leaved varieties of large maples are cultivars of Acer platanoides. It grows 40-60 feet high with a slightly narrower spread. The bark is gray-brown in color and becomes scaly as the tree matures. The young bark is more attractive as it is a silvery color and smooth.

In the early spring the tree puts form somewhat showy red flowers at the buds. Up close, the flowers are not particularly attractive, but at a distance they create a fair effect on the tree. Following the flowers, 2-4 inch long green leaves emerge (new leaves may be tinged with red overtones). The leaf has three lobes, though five-lobed leaves may sometimes develop, and a doubly-serrated margin. The underside of the leaf is a silver-gray color. The petiole is 2-4 inches long and is often red. In fall the tree puts on a spectacular show as the leaves change to a very bright red color.

The samaras are 1 inch long and the wings appear to be droopy. The wings may have a red hue, but the coloring is not dependable.

Landscape Use

Red Maples are very popular as shade trees and parking strip trees. They work best when put somewhere where they can show off their fall color.

Points of interest

It is becoming increasingly popular across the country, but it can struggle in our climate because it frequently develops magnese chlorosis in our alkaline soils, followed by leaf burn, defoliation and die back.

Notable Cultivars

Red Sunset This variety produces some of the best fall color. It also has an attractive pyramidal or oval shape. Grows to 45 feet high and 35 feet wide.


Acer x freemanii - Armstrong A hybrid cultivar of Red Maple and Silver Maple. It grows 50 feet high and 15 feet wide. Unfortunately the fall color on the Armstrong Maple is inconsistent, and often consists of a mottled mix of orange and yellow. The leaves have five lobes.


Acer x freemanii - Autumn Blaze Also a hybrid of the Red and Silver Maples, it has long-lasting red fall color and a good form thanks to a strong central leader. It grows to 50 feet high and wide.