What Is the Fast-Growing Weedy Tree With Long Leaves and a Bad Smell? Identifying Tree of Heaven

There is a tree that seems to appear out of nowhere — springing up along fence lines, in alleys and vacant lots, at the edge of parking lots and railroad tracks, and out of cracks in the pavement — and grows with startling speed, sometimes several feet in a single season. Break a leaf or snap a twig and it hits you: a strong, unpleasant odor often compared to rotten peanut butter or burnt cashews. That combination — fast, weedy growth in disturbed ground plus a foul smell — is the signature of tree of heaven (Ailanthus altissima), a native of China that has become one of the most aggressively invasive trees in North America. It is worth learning to recognize for another reason, too: it is the preferred host plant of the spotted lanternfly. Here is how to identify it and separate it from the native trees it mimics.

How to Identify Tree of Heaven

Tree of heaven has large, feather-like compound leaves that fool a lot of people into thinking it is a sumac, walnut, or hickory. The details — especially at the base of each leaflet — sort it out:

• Big compound leaves: each leaf is 1 to 3 feet long and made up of 11 to 25 (sometimes more) paired leaflets arranged along a central stalk, giving the whole tree a tropical, feathery look
• The base-of-leaflet teeth: this is the key clue — each leaflet is mostly smooth-edged except for one or two rounded, bump-like teeth near its base, often with a tiny gland underneath; no native look-alike has this exact pattern
• The smell: crushed leaves, twigs, and bark give off a strong, rank, offensive odor — the reason one of its nicknames is "stinking sumac"
• Fast, weedy growth: it grows extremely fast, sprouts aggressively from roots and stumps, and colonizes disturbed, sunny ground — roadsides, fence rows, lots, and pavement edges
• Seeds: female trees carry large, showy clusters of papery, single-winged seeds (samaras), each with a twist near the middle, turning from greenish to pink-tan to reddish-brown and often hanging on well into fall and winter
• Bark and twigs: smooth, pale gray bark (often likened to a cantaloupe rind) and stout twigs with large, heart- or shield-shaped leaf scars

A fast-growing tree with 1-to-3-foot feathery leaves, smooth leaflets bearing just a couple of rounded teeth at the base, a rank smell when crushed, and drooping clusters of twisted winged seeds is tree of heaven. The base-of-leaflet teeth plus the smell are the most reliable combination.

How to Tell It From Sumac, Walnut, and Hickory

Several native trees have similar feather-like compound leaves, and telling them apart keeps you from mistaking a beneficial native for the invader — or vice versa:

• Staghorn and smooth sumac: the leaflets are toothed all the way along their edges, not just at the base, and sumac carries upright, cone-shaped clusters of fuzzy deep-red fruit rather than hanging papery samaras — and sumac has no foul smell
• Black walnut and hickory: their leaflets are finely toothed along the entire margin, and they produce hard, round nuts instead of winged seeds; walnut leaves have a distinctive but different (spicy, not rank) scent
• Smooth margins are the tell: if the leaflets are essentially smooth-edged except for a bump or two near the base, and the crushed foliage smells bad, you are looking at tree of heaven, not a native

Why It Matters — Invasive, and the Lanternfly Connection

Tree of heaven is not just a nuisance sprout. It grows fast, reproduces prolifically by both seed and root suckers, and releases chemicals into the soil that suppress the growth of nearby plants, letting it form dense stands that crowd out native trees and vegetation. It damages pavement, foundations, and sewer lines with its vigorous roots, and it is difficult to kill — simply cutting it down usually triggers a burst of new suckers. On top of all that, it is the favored host of the spotted lanternfly, an invasive planthopper spreading across much of the eastern United States; lanternflies feed and lay eggs heavily on tree of heaven, so a stand of it can act as a nursery for the pest. If you find one on your property and want it gone, cutting alone rarely works — the usual guidance is to treat it with an appropriate herbicide method or consult a professional, and to check the trunk and nearby surfaces for the lanternfly's gray, mud-like egg masses in fall and winter.

Quick field call: a fast-growing tree with 1-to-3-foot feathery leaves, leaflets smooth except for a rounded tooth or two at the base, a rank smell when crushed, and clusters of twisted winged seeds is tree of heaven — invasive, hard to kill, and the spotted lanternfly's favorite host.

Not sure whether that fast-growing tree in the fence line is invasive tree of heaven or a native sumac, walnut, or hickory worth keeping? Snap a photo of a whole leaf, a leaflet base, and any seeds, and let Spotter help you identify it — so you know what you are dealing with before you decide whether it stays.