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Native Plants of PA: Red Maple (Acer rubrum)

Red maple (Acer rubrum) is a native tree to the United States and is found across the state of Pennsylvania. This article describes red maple biology, ecology, and use in landscaping.

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Updated:

November 17, 2025

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Red maple fall foliage

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Background

Red maple (Acer rubrum), also known as scarlet maple, is in the Soapberry Family (Sapindaceae). Red maple is one of the most widely distributed trees in eastern North America. The genus Acer originates from Latin, meaning “sharp-pointed,” and the specific epithet rubrum is Latin for "red," in reference to the color of the leaves, flowers, and buds of the plant.

A distribution map of red maple in North America. Red maple can be found from Maine to Florida and west to Minnesota and eastern Texas. — Photo credit: Biota of North America Program, *Acer rubrum*

Description

Size

Red maple is a fast-growing tree that reaches 40–60 ft in height, often with a narrow crown at maturity. The average longevity of red maple is around 80-100 years.

Flowers

Red maples are one of the earliest flowering trees in Pennsylvania forests. The red flowers emerge as early as February and can be seen through April before leaves form. Flowers are wind and insect-pollinated. Red maple trees are polygamodioecious, meaning an individual tree will be “mostly male” or “mostly female”, where most flowers on a tree will be one sex and a few will be bisexual, or contain both male and female parts. This is apparent later in the season, when one tree will be laden with fruit, and a neighboring individual will have a sparse yield.

A single female flower at the tip of a growing branch on a red maple. — *Male flowers (left) and female flowers (right) of red maple. (Photo credit: Cathryn Pugh)*

Fruit

Red maples are prolific seed producers, with individual trees bearing fruit after four years of establishment. A pair of winged seeds called samaras replaces the flowers in April. The samaras form a "V" shape, with the heavier seeds attached together at the base of the "V", and a papery bract or wing extending off each seed. Red maple samaras are the smallest of all maples in Pennsylvania, about 5/8 - 3/4 inches long. The seeds are often green in color, transitioning to red on the wings. The wind-dispersed samaras will spiral as they drift to the ground, giving them the colloquial name "helicopters".

Seeds will either germinate immediately and establish within the first 3-4 months, or they will persist in the leaf litter to germinate the following year.

*A cluster of red maple fruits, called samaras. (Photo credit: Cathryn Pugh)*

Leaves

Red maples have simple, opposite leaves with serrated margins and 3 palmate lobes. The leaves are dark green on top and paler green on the underside. Red maple is a deciduous tree that loses its leaves in autumn and is one of the earliest trees in Pennsylvania to change color. As the name suggests, leaves will turn red, as well as yellow and orange, often all on the same tree.

A red maple leaf with dark red fall foliage. — *Red maple leaves, highlighting fall color variation (photo credit: Cathryn Pugh).*

Buds

The red buds are oppositely arranged on the stem. At the tip of a twig, the terminal bud will sit between two smaller accessory buds. The bud scales have a valvate arrangement, where two scales come together and touch at their edges, resembling the halves of a shell.

Stems

Red maples can have one main stem or be clustered with multiple stems, a result of stump sprouting, a reproductive strategy in which new shoots grow from the base of the tree or stump. The bark is gray and changes texture with size and age. Smooth bark is present when the tree is young, and the bark changes to vertical cracks forming plates with increased age and diameter.

Wildlife Uses

Red maple has benefits across the food chain from insects to birds to mammals. It is a host plant to over 250 species of moth and butterfly caterpillars, including North America’s largest native moth, the cecropia moth (Hyalophora cecropia). Other insect species are attracted to the red maple’s spring flowers and, along with the associated caterpillars, provide an important early spring food source at a crucial time for many bird species. Resident birds have depleted their fat stores to survive the cold weather; therefore, early food sources are important for survival. Migrant birds have endured a long flight to reach their summer breeding grounds and will be seeking good food sources to build up energy for nest building and egg laying. The native insects associated with red maple are crucial for bird populations. In addition to serving as food sources, stands of red maple are a preferred microhabitat for the foraging of red-eyed vireos and serve as nesting trees for American redstarts and downy woodpeckers.

Twigs, bark, and leaves of red maple are used by browsing and gnawing animals; deer and rabbits will browse stump sprouts, and small mammals like voles will gnaw the bark to consume the outer and inner bark. Squirrels and chipmunks will store the seeds, and the buds are an important food source for squirrels when stored food is gone in late winter and early spring. Red maple makes a suitable cavity tree, whether alive or as a standing dead tree, also known as a snag. They are commonly used by wood ducks, barred owls, and some bat species.

Use in the Landscape

As a medium to large-sized tree, red maple requires an area with room to fill in and grow tall. Record sizes for red maple have been measured at well over 100 feet tall and wide. In the landscape, red maples can easily attain heights of 50 feet with similar widths. Red maple can make an excellent specimen tree with numerous cultivars on the market, which can be utilized for their unique aesthetics and growing characteristics. To maintain these traits, cultivars of red maple are typically propagated using root cuttings from named, desirable specimens. These are cloned duplicates that retain specific traits desirable for landscape design. There are many cultivars of red maple on the market with different characteristics, including leaf color, fall leaf retention, hardiness zone, and form (e.g., columnar vs oval). Some cultivars are hybrids of silver maple (Acer saccharinum) and should be labeled as Acer x freemanii, but are sometimes mislabeled as Acer rubrum. Hybridization occurs naturally between these species in areas of overlap, but the traits of the silver maple may or may not be desirable. Cultivars, that are in fact hybrids, include: 'Armstrong', Autumn Blaze®, Celebration™, 'Morgan', Scarlet Sentinel™, and Sienna Glen®. Most nurseries sell cultivars for their predictable habit, which is useful when planting specimen trees. It is important to research the cultivars you have available to ensure they meet the site requirements of your landscape and your specific needs.

A photo of a red maple tree taken at a distance to show its form in the landscape. — *The form of red maple. (Photo credit: Cathryn Pugh)*

When planting for wildlife habitat, restoration, or in groupings to replicate a more natural environment, bareroot seedlings are preferred. Seedlings are less expensive, and their genetic diversity may be more desirable. At the cost of predictable traits and time waiting for height in the landscape, seedling-grown trees are more genetically diverse and may be more adaptable to pests and environmental change. See the Penn State Extension article Planting Bare Root Tree Seedlings for more detailed information.

Site Conditions

Red maple is a generalist, adapted for a wide range of site conditions from wet habitats with associates like silver maple and black gum (Nyssa sylvatica), to well-drained upland sites with sugar maple, beech (Fagus americana), black cherry (Prunus serotina), and black birch (Betula lenta). The tree has been noted as having the widest range of adapted growing conditions of any other in North America. Red maple can grow in a wide range of light conditions, from full sun to moderate shade, and has a broad adaptability to hardiness zones, ranging from USDA zones 3 to 9. Red maple is adaptable to varying soil pH levels, but its fall color is best in more acidic soils. Alkaline soils, common of urban soils, generally will not provide the same fall color.

When planting a red maple, ensure that the root flare is above the soil line. Planting too deeply will cause problems for root growth and trunk health. While being an adaptable species, red maple requires consistent watering, especially during establishment. Even mature, established trees may require irrigation during drought if soil conditions are extremely dry for prolonged periods. This is especially true when planted as a specimen, with little shade from neighboring trees. These conditions are not uncommon during the height of Pennsylvania summers. Mulching can help with moisture retention and weed prevention. Proper mulching should be done at a depth of 2-4 inches, ideally extending out to the drip line of the tree. It is critical to keep mulch off the trunk of the tree. Never volcano mulch.

Trees should be protected from deer browse and buck rub for several years, until the tree has outgrown the height at which deer browse, and has developed a strong protective bark. Mesh wire extending 4 feet up the tree in landscape plantings offers airflow while providing protection from rub. Larger specimen trees are tall enough to extend past browse height but tender bark should still have protection. Tree tubes are used for smaller seedlings to provide protection from browse and herbicide applications. See the Forest Landowner Guide to Tree Planting Success for more information on tree shelters.

Several diseases and pests can afflict red maples, including the invasive spotted lanternfly. In many cases, these can be avoided with good cultural care. Red maples are an excellent alternative to the once widely used and invasive Norway maple. The benefits they provide to wildlife and the brilliant fall colors far outweigh any potential problems.

Cultural uses

The sap of red maples can be used in making maple syrup, although it has a lower sugar content than that of the preferred tree, the sugar maple (Acer saccharum).

Medicinally, the bark of red maple has and continues to be used by Native Americans as an analgesic eyewash for cataracts, and a topical application to treat hives.

The wood products industry splits maples into two groups, soft maple and hard maple, based on the wood hardness of the maple species. In Pennsylvania, hard maple refers to sugar maple, and soft maples include red maple, silver maple, box elder (A. negundo), and striped maple (A. pensylvanicum). Soft maple wood is easier to work with, compared to hard maple, and is used for veneer, pulpwood, musical instruments, and crates.