Quercus coccinea

Scarlet Oak

Botanical Name: Quercus coccinea
Family: Fagaceae
Origin: Eastern North America
Plant Type: Large deciduous shade tree

Overview

Scarlet Oak is one of the most spectacular deciduous trees available for South Australian gardens, earning its name from the extraordinary blaze of scarlet and crimson it produces each autumn. A bold, long-lived specimen, it develops a pyramidal shape in youth before broadening into a grand, wide-spreading open canopy — the kind of tree that becomes a garden landmark for generations. Fast-growing and adaptable to a range of soils including clay, it thrives in SA's temperate and Mediterranean-style climates where cold winters unlock its most brilliant colour.

Key Features

• Mature Size: 18 m H × 10 m W
• Growth Rate: Fast; 30–60 cm per year when young; strongly pyramidal in youth, broadening progressively into a wide, open, rounded canopy with horizontal branching at maturity
• Foliage: Large, deeply lobed, glossy dark green leaves with deeply cut sinuses that give each leaf an almost skeletal, architectural quality; leaves emerge slightly bronze in spring before hardening to rich green
• Flowers: Pendulous yellow-green catkins (male) in spring alongside emerging foliage; non-fragrant; ornamentally minor but provide early-season nectar for pollinators
• Seasonal Interest: Brilliant scarlet to crimson autumn colour — among the most vivid of any deciduous tree in SA; acorns mature over two seasons, starting green before turning pale brown with a deep cap
• Wildlife Value: Acorns provide food for native birds, rosellas, cockatoos, and small mammals; spring catkins support early-season bees and pollinators
• Tolerance: Frost hardy (tolerates heavy Adelaide Hills frosts); heat tolerant through SA summers; moderately drought tolerant once well established; clay tolerant; wind tolerant once the root system is anchored
• Planting Density: Specimen planting — allow a minimum of 8–10 m clearance from buildings, paved surfaces, and underground services to accommodate the mature 10 m spread and trunk flare; avenue or parkland planting — space trees 10–12 m apart centre-to-centre for a grand canopy corridor
• Pet Friendly: Toxic — acorns, leaves, and bark contain tannins that are harmful if ingested in quantity by dogs, cats, and especially horses and livestock; rake fallen acorns away from areas accessed by pets and animals

Where It Works Best

• Sunlight: Full sun; best autumn colour is achieved in an open, fully sun-exposed position — shaded trees produce muted tones
• Soil: Adaptable to sandy, loam, and clay soils; Speciality Trees note it performs particularly well in freely draining sites and sandy soils; tolerates moderately heavy clay provided drainage is managed
• Water Needs: Establishment (first 2–3 years): deep watering 2–3 times per week during summer and warm autumn, tapering to once weekly in cooler months. Established: summer — one deep weekly soaking during prolonged dry spells; winter — SA rainfall typically sufficient, supplemental irrigation rarely needed
• Maintenance: Low once established; prune only to remove dead, damaged, or crossing branches in late winter while fully dormant; no routine feeding required in reasonable soils; rake or blow fallen acorns from paths and lawn areas in late summer
• Lifespan: 200–500+ years; a genuine multigenerational specimen
• Climate Zones: Ideal for Adelaide Hills and Mount Lofty Ranges where cold winters drive outstanding autumn colour; performs well across temperate Adelaide metropolitan suburbs and SA's inland wine regions (Barossa Valley, Clare Valley, McLaren Vale, Coonawarra); not suited to tropical or subtropical conditions
• Soil pH: Prefers mildly acidic to neutral (pH 5.5–7.0); avoid highly alkaline soils which can trigger interveinal chlorosis on the foliage

Landscape & Design Ideas

• Plant as a majestic lawn specimen on acreage or in spacious suburban gardens where its full 10 m spread and 18 m canopy can be appreciated from a distance — position where the low western sun will backlight the autumn foliage
• Create a dramatic seasonal avenue along a long driveway or property boundary by planting trees at 10–12 m centres, delivering a tunnel of green in summer and a corridor of scarlet fire each autumn
• Pair with evergreen understorey plantings — ornamental grasses, low native groundcovers, or dense shrubs — to keep the garden looking complete and full when the tree is bare through winter

Why You Will Love It

If you want one tree that will stop people in their tracks every single autumn, Scarlet Oak is that tree. No other deciduous oak delivers quite the same intensity of colour — not russet or burnt orange, but a true, saturated scarlet that glows incandescently in the low autumn light. Buy it young, plant it in the right spot, and it will still be standing — and still blazing — long after everything else in the garden has changed many times over.