Tree · Sapindaceae
Sugar Maple
Acer saccharum
Give it deep, moist soil and room to spread, and the sugar maple pays you back with shade and fire-bright fall color.
Full sun
Every 7–14 days
USDA 3–8
39–79 ft · 12–24 m
Overview
The sugar maple is the tree behind New England's autumn and the bottle of syrup on the table. It grows slowly into a broad, rounded shade tree that can top 80 feet (24 m), with a heavy trunk and a dense canopy that throws cool shade all summer. Come fall, the leaves blaze through orange, red, and gold, which is the show most people plant it for.
This is a tree for cold country. It is hardy from zones 3 through 8 and shrugs off winters down to -40°F (-40°C), but it has no patience for the heat, salt, and packed soil of a tight city lot. Give it deep, fertile, evenly moist ground with room for the roots to run, and it settles in for generations.
Patience is the price of admission. Sugar maple grows slowly and lives long, so you plant it for the decades ahead rather than next season. In late winter its sap runs sweet, which is why sugarhouses across the north tap it every spring to boil down maple syrup.
Care
The short version: plant in full sun to part shade, in deep, fertile, evenly moist but well-drained soil, give it about an inch of water a week through heat and drought, and keep it well clear of pavement and road salt.
Light
Sugar maple grows best in full sun and takes partial shade in stride, especially when young. More sun feeds fuller fall color and a denser crown, though a half-day of light still raises a healthy tree.
Water
Keep the soil deep and evenly moist, watering roughly every 7 to 14 days when rain falls short. During real heat or drought, give an established tree about an inch of water a week to head off the leaf scorch this species is prone to.
Soil
Plant in deep, fertile loam that holds moisture yet drains freely and runs high in organic matter. A pH from 5.5 to 7.0, slightly acidic to neutral, suits it, and it flatly refuses compacted, soggy ground.
Temperature
This is a cold-hardy tree, comfortable from -40°F to 95°F (-40°C to 35°C). It earns its keep in the north and struggles where summers turn long and hot.
Humidity
Ordinary outdoor air is all it asks, so there's no humidity target to hit. Airflow and steady soil moisture do far more for its health than anything in the air.
Feeding
Feed in early spring with a balanced slow-release tree fertilizer, and let a soil test tell you how much it actually needs. A ring of mulch around the drip line feeds the roots slowly as it breaks down.
Pruning
Cut only in summer or full dormancy to take out dead, damaged, or crossing limbs, because a maple pruned in late winter or early spring bleeds sap heavily. Wipe your tools between cuts with 10 percent bleach or 70 percent alcohol so you don't carry disease from branch to branch.
Repotting
Sugar maple is a landscape tree, not a container plant, so repotting rarely comes up. Watch nursery or potted stock for roots circling the trunk flare or top growth that lags a crowded root ball, and tease those roots loose before planting.
Size & spacing
Give this tree real room. It reaches 40 to 80 feet (12 to 24 m) tall and spreads 30 to 60 feet (9 to 18 m) wide, so site it well clear of houses, drives, and power lines.
When to plant
Sugar maple goes in the ground in spring or fall, while the weather is cool and the roots can settle before stress arrives. The greenish-yellow flowers open in April, just before or with the leaves, and the real payoff comes in autumn when the whole canopy turns red, orange, and gold.
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: Inconspicuous greenish-yellow flowers in April before or with the leaves; brilliant red, orange, and yellow fall color
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Most sugar maple trouble shows on the leaves first, whether it's heat, a soil fungus, or a wet spring. Learn to read those signs and you can tell a cosmetic blemish from a real threat. Match what you see below before you reach for a sprayer.
One side of the tree wilting and dying back on its own
When a single limb or one whole side fades while the rest looks fine, suspect Verticillium wilt, a soil fungus that plugs the tree's water channels from inside. Peel back the bark on a wilting branch and look for green or brown streaks in the wood, then send a sample to a lab, since most maple diseases can't be told apart by eye. There is no cure, so prune out dead wood as it appears and keep the tree watered and fed to stretch its remaining years.
Fix:
- There is no cure; prune out dead branches as they appear
- Water about one inch per week and fertilize based on a soil test to prolong tree life
- Mulch around the drip line and sanitize pruning tools with 10 percent bleach or 70 percent alcohol between cuts
Brown, scorched edges between the leaf veins in hot weather
This is leaf scorch, and it shows up when the roots can't pull enough water to keep up with a hot, dry spell. Salty soil, compaction, or a cramped root zone near pavement make it worse. Water established trees with about an inch a week through heat and drought, and spread mulch over the roots to hold what moisture there is.
Fix:
- Water established trees with about one inch of irrigation per week during heat and drought
- Mulch over the root zone to conserve moisture and moderate soil temperature
- Avoid salt accumulation and soil contaminants around the roots
Glossy black tar-like spots on the leaves in late summer
Those thick, shiny black blotches ringed with yellow are tar spot, a leaf fungus that looks alarming but does little real harm. Rake up and destroy the fallen leaves each autumn, since that's where the fungus waits to start again. On a small tree you can spray a copper fungicide at leaf-out, but for most maples it isn't worth the effort.
Fix:
- Rake up and destroy fallen leaves where the fungus overwinters
- If desired on small trees, apply a copper-based fungicide, mancozeb, or triadimefon three times at two-week intervals starting at spring leaf unfurl
Brown blotches and dead buds after a cold, wet spring
A long, cool, wet spring sets up anthracnose, a fungus that browns the leaves along their veins, kills buds, and leaves crooked twig dieback behind. Rake and destroy the infected leaves so spores don't carry over. Better airflow and dry foliage keep it from taking hold in the first place.
Fix:
- Rake and destroy fallen infected leaves
- On valuable small trees, spray a copper-based fungicide, mancozeb, or chlorothalonil three times at two-week intervals from spring leaf emergence
Toxicity
Good news on every front here. Sugar maple is safe for people, pets, and livestock alike, and its boiled-down sap is the very syrup we pour on pancakes. The wilted-leaf poisoning that worries horse owners comes from red and silver maple, not from this tree.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe around cats. A curious cat that nibbles a fallen leaf has nothing to fear from this tree.
Dogs None
No concern for dogs. The leaves, bark, and twigs hold nothing that troubles them.
Horses None
Sugar maple is safe for horses. The notorious red-blood-cell poisoning comes from wilted red maple and silver maple leaves, not from this species.
Rabbits None
Rabbits can browse the foliage without harm.
Livestock None
Cattle, goats, and sheep graze near sugar maples with no ill effect.
Birds None
Birds nest and feed in the canopy safely, and the seeds feed plenty of wildlife.
People None
Safe for people. The boiled-down sap is the source of maple syrup, so part of this tree literally lands on the breakfast table.
Non-toxic to cats and dogs. Note that it is the related red maple (Acer rubrum) whose wilted leaves are notoriously toxic to horses; sugar maple is not the species classically implicated, but as a general precaution wilted maple leaves of any species are best kept away from horses.
Varieties
Most sugar maples sold for the yard are named cultivars chosen for tougher leaves and brighter fall color. These are the ones worth asking for by name.
Green Mountain
A heat- and drought-tolerant pick that holds a dense oval crown and turns orange-red in fall.
Legacy
A vigorous, scorch-resistant cultivar with thick, glossy leaves that shrug off tearing and drought.
Fall Fiesta
A tough, fast-establishing tree prized for dependable yellow-orange to red autumn color and leaves that hang on late.
How to propagate
You can grow a sugar maple from seed with a little cold treatment, but the named selections only stay true when they're grafted.
SeedModerate
Sow outdoors in fall or after 60-90 days of cold, moist stratification before spring sowing · 1 to 2 growing seasons
Sugar maple seed won't sprout until it has been through a cold spell, so sow it outdoors in fall or give it 60 to 90 days of cold, moist stratification before a spring sowing. Expect a young tree to settle in over 1 to 2 growing seasons. You can also start the species from layering or stem cuttings.
GraftingDemanding
Late winter (bench graft) or summer (budding) · 1 to 2 seasons
Named cultivars like Green Mountain and Legacy won't come true from seed, so growers graft or bud them onto seedling rootstock instead. Bench grafting is done in late winter and budding in summer, and the union knits over 1 to 2 seasons. It takes a steady hand, which is why this is the demanding route.
Myths
All maples, including sugar maple, are deadly poisonous to horses.
The danger belongs to red maple and silver maple, whose wilted leaves can wreck a horse's red blood cells. Sugar maple is not the culprit, and far from being poisonous, it is the tree we tap for maple syrup.