Tree · Sapindaceae
Red Maple
Acer rubrum
Fast-growing and easy, the red maple lights up fall with brilliant red and orange leaves.
Full sun
Every 7–14 days
USDA 3–9
39–89 ft · 12–27 m
Overview
Red maple is one of the most common trees across eastern North America, and it earns its place. It grows fast, takes to almost any soil from clay to sand, and shrugs off cold all the way down to -40°F (-40°C). The name fits the whole year: red flowers in late winter, red samaras in spring, red leafstalks through summer, and a blaze of red and orange in fall.
It is an adaptable tree that handles wet ground and the odd flood far better than most, which is why you find it in swamps and along streams as readily as in a front yard. The trade-off is its wood. Red maple is a soft maple, and the same quick growth that gives you a shade tree in a hurry also leaves brittle limbs that storms can tear apart.
Plant it for the fall show and the easy care, but give it room. A mature tree reaches well over 40 feet (12 m) with a broad crown and shallow, spreading roots that can lift sidewalks and dull a mower blade. Set well back from pavement, it asks for very little once it's growing.
Care
The short version: full sun to part shade, moist and slightly acidic soil, and steady water while it's young. It barely needs feeding, but it does need early structural pruning to keep its brittle limbs from breaking in storms.
Light
Red maple grows best in full sun but takes partial shade in stride. More sun usually means stronger fall color and a denser crown, so give it an open spot if you can.
Water
It likes moist soil and tolerates wet sites and the occasional flood, which sets it apart from most shade trees. Water young and street trees through dry spells, but an established tree is adaptable and handles medium-to-wet ground on its own.
Soil
Plant in average, well-drained soil. The tree adapts to clay, loam, and sand, but it truly prefers moist, slightly acidic ground at pH 4.5 to 6.5. Push past about pH 6.5 and the leaves start yellowing from locked-up manganese and iron.
Temperature
This is a tough, cold-hardy tree, comfortable across a huge range from -40°F to 100°F (-40°C to 38°C). That range covers USDA zones 3 through 9, so winter cold is rarely the problem.
Humidity
Ordinary outdoor humidity suits it fine, with no number to manage. The tree's real preference is for moisture at the roots, not in the air.
Feeding
Established red maples rarely need feeding in decent soil. If you do feed, use a balanced or low-nitrogen, higher-potassium mix in spring. On alkaline ground, manganese chlorosis may call for soil acidification or a micronutrient treatment instead.
Pruning
Prune in late summer or fall to avoid the heavy spring sap bleeding maples are known for, taking out dead, weak, and crossing limbs. Because the wood is brittle, focus early pruning on removing narrow, weak branch angles that storms would snap.
Repotting
none
Size & spacing
Red maple is a large tree, commonly 40 to 70 feet (12 to 21 m) tall with a crown spreading 30 to 50 feet (9 to 15 m). Give it plenty of room and keep it well back from sidewalks and driveways, since its shallow roots buckle pavement.
When to plant
Red maple is a long-lived tree, so the planting season is short and simple. Set young trees out in spring or fall while the weather is mild, and the tree handles the rest. Look for red flowers as early as late winter, samaras in spring, and the famous color in fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Red flowers late winter to early spring (roughly January-April); red to yellow samaras mature in spring; brilliant red-orange-yellow foliage in fall.
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
A healthy red maple gives little trouble, but a few problems are worth knowing on sight. Most trace back to soil that's too alkaline, a soilborne fungus, or the tree's own brittle wood. Match what you see below and act before a small issue becomes a hazard.
Branches wilt and die on one side of the tree
This is verticillium wilt, a soil fungus that creeps into the water-carrying vessels and chokes off whole branches. Peel the bark on a wilting limb and you'll often see green to black streaks in the sapwood, along with undersized leaves and a heavy crop of seed. There's no cure, so prune out and destroy the dead wood, disinfect your tools between cuts, and keep the tree watered to help it cope.
Fix:
- Prune out and destroy (burn or landfill) dead branches; do not compost
- Disinfect tools with 10 percent bleach or 70 percent alcohol between cuts
- Water and fertilize with low-nitrogen, higher-potassium fertilizer to support recovery
Yellow leaves with green veins on the newest growth
This is manganese chlorosis, and it shows up when the soil pH climbs above 6.5 to 7.0 and locks up the iron and manganese the tree needs. Limestone, concrete, and over-liming near foundations and pavement are the usual culprits. Test the soil, work it back toward slightly acidic with elemental sulfur, and treat with chelated manganese or iron if the yellowing is bad.
Fix:
- Test and lower soil pH toward slightly acidic with elemental sulfur
- Apply chelated manganese or iron as a soil or foliar treatment
- Mulch and improve drainage to reduce nutrient stress
Limbs split and break after ice, snow, or wind
Red maple is a soft maple with brittle wood, and its fast growth leaves it full of narrow, weak branch crotches that tear apart in storms. Clean up broken and hanging limbs right away with proper cuts, and call an arborist for anything large or overhead. The real defense is structural pruning while the tree is young, training a single strong leader and wide branch angles so storms have less to grab.
Fix:
- Remove broken and hanging limbs promptly with clean cuts
- Structurally prune young trees to favor strong, wide branch angles
- Consult an arborist for large or hazardous limbs
Toxicity
For a home with cats and dogs, red maple is safe. The serious danger is to horses, and it is severe: wilted or dried red maple leaves destroy a horse's red blood cells and can kill within days. Never let horses reach fallen branches, raked leaves, or prunings.
Toxic to
Horses · Rabbits · Livestock · Birds
Safe for
People · Cats · Dogs
Horses Severe
This is the deadly one. Wilted or dried red maple leaves destroy a horse's red blood cells, and the first signs are weakness, a poor appetite, and a dull, depressed mood. Watch for darkened brown or blue gums, red-brown urine, colic, and laminitis, and call a vet at once, since death can follow within 18 hours to 10 days and pregnant mares may abort.
Rabbits Caution
There's no safe-feeding data for rabbits and the same blood-cell toxin could harm them, so keep red maple leaves and prunings out of the hutch.
Livestock Caution
Cattle, sheep, goats, and other grazers should be kept off wilted maple leaves and fallen branches, since the toxin that floors horses can affect related animals too.
Birds Caution
Little is known about how birds react, so treat the wilted leaves as a risk and don't let poultry or pet birds graze on raked clippings.
Cats None
The ASPCA lists red maple as non-toxic to cats, so a curious nibble is nothing to worry about.
Dogs None
Dogs handle red maple fine. It carries no toxicity for them, and chewing a fallen leaf or samara won't make a dog sick.
People None
Red maple poses no real danger to people. It isn't a food plant, but handling the tree, leaves, and seeds is harmless.
Horse owners must keep horses away from red maples and, critically, from fallen branches and raked or wilted leaves, which are the deadly form. Do not dump maple prunings or leaves where horses can reach them. The tree poses essentially no toxicity risk to cats or dogs.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Most red maples sold for the garden are named cultivars, chosen for reliable fall color and a clean shape. These are the ones you'll meet most often.
October Glory
A favorite for its dependable red-to-orange fall color that holds for weeks and arrives late in the season.
Red Sunset (Franksred)
One of the most widely planted maples, prized for strong orange-red fall color on a vigorous, neatly upright tree.
Brandywine
A seedless male tree that turns brilliant scarlet in fall before deepening to a reddish purple.
Red Rocket
A narrow column of a tree, roughly 40 feet (12 m) tall and only about 15 feet (5 m) wide, made for tight spaces.
How to propagate
Red maple grows easily from seed, but seedlings are a gamble on fall color. To keep a cultivar's exact traits, growers reach for cuttings or grafting instead.
SeedEasy
Sow fresh samaras in late spring to early summer as they ripen; some seed lots benefit from cold stratification. · 1 to 2 growing seasons
Growing from seed is the easy route. Sow the winged samaras fresh in late spring to early summer as they drop, cold-stratify any stubborn lots, and give them one to two growing seasons to settle in. Just know that seedlings vary, especially in fall color, so a named cultivar won't come true this way.
Stem cuttingsModerate
Take softwood cuttings in early summer. · Several weeks to root, then a season or more to establish.
Softwood cuttings work, though results are hit or miss. Take them in early summer, and expect several weeks for roots to form and a season or more before the young tree is truly established.
GraftingDemanding
Bench graft or bud in the dormant or growing season onto seedling rootstock. · 1 or more seasons
Grafting is how nurseries keep a cultivar true, since it never comes true from seed. Bench graft or bud onto seedling rootstock in the dormant or growing season, then count on a season or more for the union to take and grow on. It's demanding work and better left to experienced hands.
Myths
Red maple is dangerous to plant near cats and dogs.
The ASPCA lists red maple as non-toxic to both. The serious, sometimes fatal danger is specific to horses eating wilted or dried leaves, so a household with cats or dogs has nothing to fear from this tree.
Only the seeds or bark of red maple harm horses.
The toxin builds in the leaves, not the seeds or bark. Wilted or dried fallen leaves are the most dangerous form of all, while fresh green leaves on the tree are far less of a threat.