Red maple
Acer rubrum
also called swamp maple, scarlet maple, soft maple
Red something in every season: crimson buds in winter, red flowers in March, red leaf stalks all summer and scarlet fall color, on the fastest and most forgiving of the big native maples.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- Red
- Sunlight
- Full sun
- Watering
- Moderate; one of the few shade trees happy in a soggy corner
- Soil
- Adaptable, acid-leaning; wet or dry, sand or clay
- Feeding
- All-purpose balanced
- USDA zones
- 3a–9a
- Frost tolerant
- Yes
- Plant out
- 14 days before the last spring frost
- Plant spacing
- 32 ft 10 in
- In-row spacing
- 26 ft 3 in
- Between rows
- 39 ft 4 in
- Square-foot density
- Not suited to SFG
- Root system
- Woody, shallow and far-reaching
- Working depth
- 12–24 in
- Can reach
- 4 ft down where the soil allows
- Spread
- 79–118 ft across, about 2–3× the width of the plant
Almost all of a tree’s roots are in the top two feet of soil, where the air is, and they run out well past the branch tips. The deep taproot most people picture belongs to the seedling; the tree grows out of it and spends the rest of its life spreading sideways instead.
Shallow, wide, and inclined to surface roots that show through a lawn and lift a nearby path. It is otherwise as tolerant a tree as there is.
The habit is Red maple’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Confirmed safe
We say a plant is safe only where a named poison-control reference names that exact species and records it as non-toxic to both cats and dogs. Most plants are on nobody’s list, and their absence here is not a judgement about them. This is a record of what those references say, not veterinary advice, and it cannot account for your own animal, the quantity eaten, or a plant treated with anything.
The famous red maple poisoning is a horse case. The ASPCA row records toxic to horses beside non-toxic to dogs and non-toxic to cats, and only the last two are read here.
- When
- Tappable like sugar maple in late winter, at a slightly weaker ratio; otherwise prune in summer or midwinter, never in spring.
- What to look for
- For pruning, full leaf or deep dormancy. A maple cut in March bleeds sap spectacularly; it does little harm but frightens everyone.
- How to harvest
- Structural pruning in the first decade: one leader, no narrow crotches, since the fast wood is softer than sugar maple's. Tap it in a sugar-bush pinch at fifty or sixty gallons of sap to the syrup gallon.
- How often
- A dormant-season look each year while young.
- Storing the crop
- Nothing to store beyond any syrup you boil. Rake the scarlet leaves onto the beds; they break down by spring.
- Leafhoppers Leafhoppers scorching soft new shoots in nursery-fresh trees
- Tar spot Tar spot freckling the leaves in wet years, cosmetic
- Verticillium & fusarium wilt Verticillium wilt, as with all maples
- Iron chlorosis Iron chlorosis on alkaline soil, yellow leaves with green veins; it wants acid ground
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Assassin bug ReduviidaeHunts Leafhoppers
A patient ambusher with a curved beak it drives into whatever it catches — caterpillars, beetles, bugs, and the occasional bee, so count it a generalist rather than a specialist. It will jab a careless finger too, so admire it and leave it be.
- Big-eyed bug Geocoris spp.Hunts Leafhoppers
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Damsel bug NabidaeHunts Leafhoppers
A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in.
- Spiders AraneaeHunts Leafhoppers
Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense.
The most common tree in eastern North America, and the March flowers are an underrated early bee plant. Named selections ('October Glory', 'Red Sunset') color reliably; a random seedling may go plain yellow, so buy the fall color you want.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com