Boxelder
Also known as
Box elder maple, Ash-leaved maple, Manitoba maple, River maple, Ashleaf maple
Keep this plant’s care guide close at hand.
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Acer negundo, commonly called boxelder, is a fast-growing, short-lived maple native to much of North America. Unlike most maples, it bears pinnate leaves with three to seven coarsely toothed leaflets, a trait that often leads to confusion with ashes. The tree is typically dioecious, with separate male and female individuals; clusters of winged samaras ripen in late summer to fall and can persist into winter. Mature trees reach 10–25 m (35–80 ft) with a broad, often irregular crown, gray to light-brown furrowed bark, and greenish twigs that may be waxy or glaucous. Boxelder thrives in riparian corridors, floodplains, and disturbed soils, tolerating seasonal inundation, drought, compacted urban sites, and a wide range of pH. Its adaptability and prolific seeding make it valuable for quick shade and erosion control, though it is sometimes considered weedy or invasive outside its native range. Wood is relatively soft and prone to storm breakage; the tree can harbor boxelder bugs. Several ornamental cultivars exist, including variegated forms that offer improved landscape appeal.
Taxonomy
Properties & Requirements
How to care for Boxelder
Water
Water newly planted boxelders deeply once or twice weekly during the first two growing seasons, adjusting for rainfall. Aim to moisten the soil 20–30 cm deep; long, slow soaks are preferable to frequent light splashes. A general guide is 10–20 liters per centimeter of trunk caliper per week during establishment. Once established, the tree tolerates drought but performs best with occasional deep watering in extended dry spells. Avoid chronically waterlogged soils; ensure surface drainage and keep mulch off the trunk.
Light
Full sun to partial shade is ideal. Best crown form and fall color occur with at least 6 hours of direct sun, though the species tolerates light shade and still grows acceptably. In dense shade, trees become leggy with weaker branch structure. Variegated cultivars typically need more light to maintain color but can scorch in very hot, dry exposures; provide afternoon shade in such climates. Ensure open sky above to reduce competition and improve airflow.
Nutrients
Boxelder generally requires little fertilization once established. In nutrient-poor or compacted urban soils, apply a thin layer (2–5 cm) of composted organic mulch annually to build structure and biology. If growth is weak, use a balanced, slow-release fertilizer (e.g., 10-10-10 or 14-14-14) at label rates in early spring, targeting the dripline. Avoid high-nitrogen spikes, which encourage weak, storm-prone growth, and never fertilize after midsummer, as late flushes reduce cold hardiness.
Temperature
Hardy in USDA Zones 2–9, Acer negundo tolerates extreme cold to about −40°F (−40°C) and summer heat in continental climates. It withstands freeze–thaw cycles and late frosts reasonably well. Young trees benefit from wind protection in very exposed, high-heat sites, where rapid growth and soft wood increase breakage risk. Avoid reflected heat pockets near large pavement expanses. In containers, provide winter root protection below 15°F (−9°C) to prevent pot freeze damage.
