Tree identification · Western Washington
Tree-of-Heaven Identification Guide for Western Washington
Tree-of-heaven ( Ailanthus altissima ) can look like sumac, walnut, or ash at first glance. Start with the leaflets: their edges are mostly smooth, with small gland-bearing teeth near the base. Then check the leaf arrangement, seeds, and bark before deciding what to do.
This visual guide pairs identification details with Sound Tree Care photographs from a Burien property. Use it to narrow down an unfamiliar tree and plan your next step.
Tree-of-Heaven Quick Facts
- Scientific name
- Ailanthus altissima
- Tree type
- Fast-growing deciduous tree
- Leaves
- Large, once-compound; alternate on twigs
- Best leaf clue
- Glands on teeth near leaflet bases
- Fruit
- Papery wings, each with one central seed
- Spread
- Seeds and shoots from established roots
How to Identify Tree-of-Heaven
- Find a whole leaf. Many individual leaflets attach along one central stalk. Trace that stalk back to the woody twig; a leaflet is only one part of the leaf.
- Inspect a leaflet base. Look for one or more rounded teeth near where the leaflet joins its stalk. Check underneath for the raised glands.
- Compare the edges. Most of the leaflet margin is smooth, unlike the saw-toothed edges of many sumacs and walnuts.
- Use a second feature. Winged seed clusters, alternate leaves, and twig or bark details help confirm the identification.
Smell is a supporting clue. Bruised foliage can have a strong, unpleasant odor, often compared to rancid peanut butter. Avoid skin contact with sap and do not rely on odor alone. A clear photo of the leaflet underside is more useful than a distant canopy photo.
Visual Identification Guide
Compare several features on the same tree. The three Burien photographs below show the tree identified by Sound Tree Care; the gland close-up is a separate reference photograph.
Leaves: many leaflets, one leaf
Look for a long central stalk carrying pointed leaflets. Whole leaves attach alternately along the twig. Leaflet counts vary, so shape and basal glands matter more than counting alone.
Glands: the detail to check closely
Turn a leaflet over and examine the base. Small raised glands occur on the underside of the rounded basal teeth. This is a more dependable clue than the tree's overall silhouette.
Seeds: papery wings, not bean pods
Female trees produce hanging clusters of winged fruits called samaras. Each has a seed near the center of a slightly twisted wing. The wings dry to tan or brown and may remain after leaf fall. Male trees do not produce these seed clusters.
Growth habit: check beyond the canopy
Tree-of-heaven can become a large tree or form groups of stems. A mature canopy is useful context, but it does not establish the species by itself. Examine reachable leaves and fallen seeds without climbing or approaching utility lines.
Bark, flowers, and winter clues
Young bark is relatively smooth; older trunks become gray-brown with shallow ridges. Twigs have large leaf scars. Small pale flowers occur in terminal clusters during the growing season. In winter, use retained seeds and twig features together—bark alone can be misleading.
Tree-of-Heaven Seedlings and Root Suckers
A small shoot may be a new seedling or growth from an older tree's roots. Root suckers can emerge away from the trunk, including after cutting or disturbance. A patch of shoots does not necessarily represent many independent seedlings.
Photograph the leaf details and the surrounding area. Note any nearby mature tree, old stump, or recent cutting. This helps an assessor understand whether the visible shoot may be part of a larger root system.
Tree-of-Heaven vs. Sumac, Walnut, and Ash
Compound foliage is shared by several trees. Use these differences to decide which details to photograph next.
| Tree | Leaf or twig clue | Fruit clue |
|---|---|---|
| Tree-of-heaven | Mostly smooth leaflet edges; gland-bearing teeth near the base; alternate leaves | Clusters of individual wings with centrally placed seeds |
| Smooth or staghorn sumac | Leaflets toothed along their edges; no matching basal glands | Dense, upright reddish fruit clusters |
| Walnut | Leaflets generally have fine teeth and lack tree-of-heaven's basal glands | Rounded nuts inside substantial husks |
| Ash | Leaves and buds occur in opposite pairs on twigs; check the whole leaf attachment | Paddle-like winged seeds with the seed toward one end |
| Mimosa / silk tree | Twice-compound foliage with many much smaller leaflets | Flat pods; pink powder-puff flowers in season |
For the finer, fern-like foliage of silk tree, see our Mimosa identification guide.
Is Tree-of-Heaven Invasive in Washington?
Yes. Washington lists tree-of-heaven as a Class C noxious weed and includes it on the state plant quarantine list. King County identifies it as non-regulated: control is encouraged but is not required there under its noxious-weed program. Check the current guidance for your county rather than assuming one rule applies everywhere.
It occurs in Washington's urban and disturbed landscapes and is a preferred host of spotted lanternfly. Identifying a host tree does not mean the insect is present. For current reporting guidance, consult the state resources below.
For Puget Sound properties: confirm ownership, nearby utilities, and any applicable city or site restrictions before scheduling removal. A weed designation does not answer every permitting question. Start with our tree permit resources.
Tree-of-Heaven Removal Starts with a Control Plan
Cutting alone can make the problem harder. An established tree can respond with stump sprouts and new root suckers. Removing the visible trunk is different from controlling the living root system.
- Confirm the identification. Check leaflets, glands, and another feature before removing a lookalike.
- Assess the site. Record tree size, access, structures, utilities, existing shoots, and previous cutting.
- Choose the sequence before cutting. A site-specific plan may require treatment before removal. Discuss appropriate methods and timing with a qualified applicator or county weed specialist; follow current product labels and site restrictions.
- Plan follow-up. Inspect for new shoots and seedlings over subsequent growing seasons. A one-time removal may not finish the job.
Small, independent seedlings may be removable while the soil is moist if the root can be recovered. Established suckers and large trees need a different approach. Keep clear of unstable stems and overhead wires.
Sound Tree Care can discuss the scope of tree removal and arborist services for your property. Confirm any herbicide treatment and follow-up responsibilities as part of the project scope.
Tree-of-Heaven Identification FAQs
What photographs should I take for identification?
Take a whole-tree view, a complete compound leaf, the underside of a leaflet base, and any fruit. Include bark and nearby young shoots if you can photograph them safely from the ground.
Can I identify it from bark alone?
Bark is a supporting feature. Leaflet glands and fruit usually provide more useful detail. If the tree is leafless, photograph twigs and any retained seeds, then have the identification checked before work.
Does every tree-of-heaven have seeds?
No. Male and female flowers occur on separate trees, and only female trees produce seed clusters. An absence of seeds does not rule out the species.
Will stump grinding stop tree-of-heaven from coming back?
Grinding removes the stump locally, but roots extending beyond it may remain alive. Include root-system control and monitoring in the plan rather than treating grinding as a guarantee against regrowth.
How much does removal cost?
Pricing depends on size, condition, access, nearby targets, debris handling, and the control and monitoring scope. Send photos and the property location so we can discuss the work that needs to be assessed.
Think You Have Tree-of-Heaven?
Send Sound Tree Care a whole-tree photo and close-ups of the leaves and seeds. Tell us whether the tree has been cut before and whether new shoots are appearing nearby. We serve Burien, Seattle, SeaTac, and surrounding Puget Sound communities.
Identification and Management References
Consult current county and state guidance when planning control. Local photographs: Sound Tree Care LLC, Burien, Washington. Leaflet-gland reference credit appears with the image.
- King County: tree-of-heaven identification and control
- Washington State Noxious Weed Control Board: tree-of-heaven
- Washington State Department of Agriculture: tree-of-heaven and reporting
- University of Maryland Extension: physical features and management
- Purdue Extension: identification and walnut comparison
- UConn Extension: identification, lookalikes, and control
