Plant of the Week: Acer Rubrum

By Davis Landscape Architecture @DavisLandArch

Acer rubrum leaf (Cambridge, 03/11/2011)

Position: Full sun to partial shade

Flowering period: Mid Spring

Soil: Well drained

Eventual Height: 25m

Eventual Spread: 12m

Hardiness: USDA Zones 4a – 9b

Family: Sapindaceae

Acer rubrum is a medium sized deciduous tree with an upright growth habit. It’s leaves are light green on the upper surface and the underside is whitish on the underside, these become red in autumn. The  leaves of the tree are palmate,  3 lobed, dark green above and a whitish under surface. Many of it’s leaves are quite variable in form. They are arranged oppositely on the twig and are typically 5 – 10 cm long with a serrated margin. The twigs are reddish in color and somewhat shiny with small lenticels. The buds are usually blunt with several loose scales, and greenish/red in color. The bark is a pale gray and smooth when the plant is young. As the tree gets older the bark becomes darker and cracks into slightly raised long plates. The trunk of this tree will achieve a diameter of up to 50cm. The flowers of the tree appear in spring, are generally unisexual, with male and female flowers appearing in separate sessile clusters. The flowers are red with 5 small petals and a 5 lobed calyx borne in hanging clusters, usually at the twig tips. The fruit is a 15 to 25 mm long double samara which is a type of fruit with flattened divergent wings. They are borne on long slender stems and are variable in color from light brown to a reddish hue. 

Acer rubrum, commonly known as the Red Maple or Soft Maple, is one of the most common and widespread deciduous trees of eastern North America. This tree can be found growing in swamps, dry soils and most anywhere in between and grows well from sea level to about 900 m. A. rubrum seldom lives longer than 150 years. It reaches maturity around at the age of 70 – 80 years. It is used on a small scale commercially for the production of Maple syrup. It was introduced into the UK in 1656 and shortly thereafter it was widely cultivated.

The etymology of the binomial name Acer is derived from the classical Latin name for the Maple. Rubrum is derived from the Latin rubra ‘red’, referring to the flowers, petioles, twigs and seed the autumn color of this tree.

Acer rubrum (Cambridge, 03/11/2011)

The landscape architect may find Acer rubrum useful as an attractive specimen tree with fantastic autumn leaf color and is suitable for a parkland setting. It is particularly useful in damp sites and is tolerant of urban pollution.

Ecologically, this plant is attractive to Lepidoptera and the seeds are eaten by a variety of mammals.

The variety Acer rubrum ‘October Glory’ has been awarded the prestigious Royal Horticultural Societies annual Award of Garden Merit in 1993.

Acer rubrum will tolerate most soil types and pH. It will tolerate a wide variety of soil moisture content, including poorly drained.

Maintenance: This plant requires little maintenance.