🍁 Acer rubrum ‘Autumn Flame’ – Autumn Flame Red Maple

🔎 Identification

Scientific name: Acer rubrum ‘Autumn Flame’.

Horticultural synonym: Acer × freemanii ‘Autumn Flame’ in some references.

Trade name: Autumn Flame Red Maple.

Family: Sapindaceae (soapberry family), formerly Aceraceae.

Common names: Autumn Flame red maple, Autumn Flame maple, red maple.

Species origin: Eastern North America, including Quebec, Ontario, the United States and areas extending to the continent's southeast.

Cultivar origin: American horticultural selection introduced by McGill & Sons Nursery, Oregon, in 1964, according to some historical references.

Type: Deciduous ornamental and shade tree.

Special feature: Especially appreciated for scarlet fall colour that appears relatively early and may persist for several weeks. Has a dense, symmetrical, rounded crown and vigorous growth. Generally considered a male cultivar, greatly limiting samara production.

Note: Autumn Flame should not be confused with Autumn Blaze® (‘Jeffersred’), a hybrid of Acer rubrum and Acer saccharinum. Autumn Flame is mainly listed as an Acer rubrum cultivar.

🌿 Botanical description

Habit: Rounded to broadly oval, with a dense, regular, relatively symmetrical crown.

Height: About 12 to 15 m at maturity, sometimes more depending on conditions.

Spread: About 9 to 12 m, potentially approaching 15 m.

Growth: Moderate to fast. Generally vigorous in sufficiently moist, fertile soil.

Trunk: Generally straight, with relatively regular structure.

Branches: Numerous, ascending to spreading, forming a dense, rounded crown.

Bark:

• Light grey to greyish brown on young trees.

• Relatively smooth during the first few years.

• Gradually becomes rougher with age.

• Shallow furrows at maturity.

Twigs: Reddish brown to greyish brown.

Leaves:

• Simple and opposite.

• Palmate.

• Generally with three to five lobes.

• Relatively pointed lobes.

• Toothed margins.

• About 7 to 10 cm long.

• Medium to dark green in summer.

• Paler underside, sometimes slightly bluish.

• Petioles often reddish.

• Young spring leaves sometimes tinged red.

• Scarlet to orange-red fall colours.

Special feature: Autumn Flame foliage is generally smaller than that of some other red maple cultivars. Its dense, symmetrical crown creates a particularly appealing silhouette for specimen or row plantings.

🌼 Flowering

Period: March to April, before or as the first leaves appear. In Quebec, flowering generally occurs later, depending on the spring thaw.

Flowering: Inconspicuous to moderately ornamental.

Flowers:

• Small flowers grouped in flower heads.

• Generally arranged in compact clusters.

• Without obvious true petals.

• May show reddish to dark red shades.

• Appear directly on twigs.

• Often visible before foliage fully unfolds.

Colour: Red to reddish.

Duration: Relatively short.

Special feature: Like many red maples, Autumn Flame flowers very early in spring. Small reddish flowers appear while branches are still leafless, making them easy to observe.

Generally considered a male cultivar. Normally produces no fertile fruit when authentically propagated from the same clone.

🍃 Fruit

Type: Paired samaras, characteristic of maples.

Shape:

• Two small joined seeds.

• Two membranous wings.

• Characteristic V-shaped arrangement.

• Structure adapted to wind dispersal.

Size: About 2 to 3 cm per samara, depending on conditions.

Colour: Generally reddish to greenish while developing, then brownish at maturity.

Ripening period: Spring to early summer in fertile red maples.

Production: Normally absent or very low in the male cultivar Autumn Flame.

Edibility: Samaras are not considered food fruit.

Special feature: Unlike female Acer rubrum cultivars, Autumn Flame is generally sold as a sterile male selection. This greatly reduces seed production and litter on lawns, driveways and paved surfaces.

🍂 Fall colour

Period: September to October, sometimes from late August, depending on the climate.

Colours:

• Scarlet red.

• Bright red.

• Crimson red.

• Reddish orange.

• Dark red.

Special feature: Autumn Flame is known for particularly early fall colour. Among the first red maples to change colour, it gradually develops relatively uniform scarlet foliage that may persist for several weeks.

Colour is generally stronger with cool nights and sunny days. Sufficiently acidic, moist soil also encourages beautiful fall colour.

🌱 Growing conditions

Exposure: Full sun to partial shade.

Soil: Fertile, deep, slightly acidic, well drained to moist.

Texture: Prefers loam but tolerates clay and sand with adequate moisture.

pH: Slightly acidic to neutral. Prefers acidic soil. Strongly alkaline soil can cause iron chlorosis.

Moisture: Prefers cool, consistently moist soil. Also tolerates temporary flooding.

Watering: Regular during the first few years and prolonged droughts.

Planting: Spring or fall. In Quebec, spring is particularly useful for establishment before winter.

Spacing: Allow about 9 to 12 m for natural crown development.

Location: Choose a sunny spot with sufficiently deep, moist soil.

Special feature: Autumn Flame prefers moist, slightly acidic soil. It tolerates various soil types, but calcareous and strongly alkaline soils can cause nutrient deficiencies and slow growth. Extremely dry locations are best avoided.

❄️ Hardiness

Zones: 3b to 8 according to some horticultural references. Other sources indicate zones 4 to 8.

Approximate minimum temperature: About -34 to -37 °C, depending on growing conditions and establishment.

Winter resistance:

• Excellent overall hardiness.

• Suited to cold regions of North America.

• Suitable for several areas of Quebec.

• Young trees benefit from protection during their first winters.

• Branches can be damaged by ice storms.

• Winter winds can increase drying of young twigs.

Special feature: Good hardiness makes Autumn Flame particularly appealing for cold regions. Some Cornell references even classify it as zone 3b. It is a useful candidate for several Quebec areas, especially where soil and location meet its moisture needs.

✂️ Care

Pruning: Formative pruning is recommended during the first few years for a strong, balanced framework.

Pruning period: Ideally summer or dormancy, avoiding heavy sap flow in early spring.

Formative pruning:

• Retain a strong central leader.

• Remove dead or damaged branches.

• Remove crossing branches.

• Correct forks with overly narrow angles.

• Encourage balanced distribution of main branches.

Fertilizing: Generally unnecessary in fertile soil. Compost may be applied in spring if needed.

Mulching: Recommended to keep soil moist and reduce grass competition.

Watering: Monitor especially during the first few years after planting and droughts.

Propagation: Mainly by grafting or vegetative propagation to faithfully retain cultivar characteristics.

Transplanting: Generally fairly easy with young trees. Prefer spring in cold regions.

Diseases and pests:

• Aphids.

• Scale insects.

• Leafhoppers.

• Wood borers.

• Verticillium wilt.

• Leaf spots.

• Marginal leaf scorch.

• Iron chlorosis in alkaline soil.

• Root rot in poorly drained soil.

Special feature: Autumn Flame generally resists major maple pests and diseases well. The most significant problems often relate to growing conditions, especially overly alkaline soil, prolonged drought and root stress.

🦋 Ecological value

• Spring flowers can provide pollen for insects.

• Red maples provide spring food for some pollinators.

• Dense foliage shelters several bird species.

• Crown provides significant shade.

• Can help reduce temperatures in urban spaces.

• Contributes to atmospheric carbon capture.

• Provides habitat for several tree-associated organisms.

Special feature: Its main ecological value lies in a large crown and ability to quickly create vegetation cover. However, as a generally seedless male cultivar, Autumn Flame provides less food for birds and small mammals than fertile female red maples.

🏡 Landscape uses

• Shade tree.

• Specimen planting.

• Municipal parks.

• Large residential properties.

• Rows of trees.

• Urban landscapes.

• Borders of large properties.

• Institutional green spaces.

• Creating shaded areas.

• Landscapes emphasizing fall colours.

Special feature: A rounded crown, early fall colour and generally absent samara production make Autumn Flame particularly appealing for large landscapes and settings where plant litter should be limited.

✅ Highlights

• Exceptional scarlet fall colour.

• Particularly early fall colour.

• Colours may last several weeks.

• Dense, symmetrical crown.

• Rounded, regular habit.

• Moderate to fast growth.

• Excellent hardiness for cold regions.

• Well adapted to Quebec's climate.

• Generally little samara production.

• Few problems from falling seeds.

• Excellent shade tree.

• Good tolerance of temporarily wet soil.

• Well adapted to urban landscapes.

• Ornamental green summer foliage.

• Strong fall ornamental interest.

• Suitable for large properties and parks.

❌ Points to consider

• Needs plenty of space at maturity.

• Can reach 12 to 15 m tall.

• Crown can exceed 10 m wide.

• Prefers moist, slightly acidic soil.

• Calcareous soil may cause chlorosis.

• Sensitive to prolonged drought.

• Surface roots can complicate lawn maintenance.

• May develop roots that lift paved surfaces.

• Formative pruning is important during the first few years.

• Very dry soil can reduce vigour.

• May be affected by Verticillium wilt.

• Fall colour can vary with environmental conditions.

• Unsuitable for small gardens.

🍁 Distinctive feature: Autumn Flame is especially appealing for announcing fall before many other trees. At the first cool nights, green foliage quickly turns beautiful scarlet, sometimes as early as late summer. Its dense, rounded, symmetrical crown creates an elegant silhouette ideal for large gardens and landscapes. Unlike many maples producing abundant samaras, Autumn Flame is generally a male cultivar with very few seeds. Hardiness, early fall colour and low fruit production make it an excellent choice for cold regions, particularly Quebec.