Invasive tree identification, one field test per tree

Compound leaves: tree of heaven first

Most invasive-tree questions in the eastern US are about a fast-growing tree with long, feather-like leaves on a vacant lot or a roadside. NC State Extension describes tree of heaven with leaves 18 to 24 inches long carrying 10 to 41 leaflets. The test is at the base of each leaflet: a notched, glandular base with the only teeth on the leaflet, and a smooth edge above it. Crushed leaves and broken stems smell strongly; descriptions range from rancid to peanut butter. The bark is smooth and pale gray, and female trees carry large drooping clusters of flat, twisted, reddish-brown winged seeds.

Sumacs and black walnut are the usual confusions; the sumac page also covers poison sumac, which should not be touched. Their leaflets are toothed along the whole edge and have no gland at the base. The tree of heaven page has the full look-alike table and the spotted lanternfly connection.

Two southern trees also have big divided leaves. Chinaberry has leaves divided twice, 12 to 24 inches long, with toothed, pointed leaflets; NC State describes fragrant lilac-colored flowers in spring and wrinkled yellow fruit about half an inch long that hangs on through winter. NC State reports the fruit as poisonous to people, cats and dogs: never eat it. Brazilian peppertree, across the Florida peninsula, has 5 to 9 leaflets that are strongly aromatic when crushed and small peppercorn-like fruit that ripens red from November to January, according to UF/IFAS.

White spring blossoms that smell: Callery pear

In March or early April, roadsides in the East and Midwest fill with white-flowering trees before anything else has leaves. The Missouri Department of Conservation describes Callery pear flowers with five rounded white petals, blooming before the leaves, and a scent many people find revolting. Leaves are glossy, oval, finely round-toothed and up to 3 inches long, often turning red or purple in fall. The fruit is round, up to half an inch across, greenish yellow with whitish spots. Planted Bradford pears are thornless, but wild seedlings and sprouts have twigs that end in thorns, which is how escaped trees in old fields give themselves away.

Ohio's rule ended sales of Callery pear on January 7, 2023, after a five-year grace period, and does not require existing trees to be removed. The Bradford pear page covers serviceberry and wild plum, the white-flowering natives it is confused with.

Maple leaves with milky sap: Norway maple

Norway maple looks like a sugar maple until you break a leaf. NC State gives leaves about 7 inches across with five sharply pointed lobes, a leaf stalk that exudes milky sap when snapped, and samaras whose wings spread in a nearly straight line. Fall color is a late, plain yellow. NC State notes the tree has been labeled invasive in several northeastern states; Minnesota allows its sale only with a label telling buyers to plant it where seedlings will be controlled. Native sugar maple has clear sap and horseshoe-shaped seeds, as the Norway maple vs sugar maple page shows.

Milky sap and popcorn seeds: Chinese tallow

Along the Gulf Coast and in the Carolinas, a small tree with broad, long-pointed leaves and bright red fall color is often Chinese tallow. NC State describes leaves about 1 to 3 inches long with a tapering base, a long pointed tip and conspicuous yellow veins, milky white sap from any damaged part, and three-parted capsules that split to show three white, waxy seeds that hang on like popcorn. No native tree in the Southeast combines those seeds with milky sap. The Chinese tallow page covers it in full.

Shrubs that become small trees

Several listed plants start as shrubs and reach small-tree size. Minnesota has listed common and glossy buckthorn as Restricted noxious weeds since 1999, autumn olive since 2026, and Siberian peashrub and saltcedar more recently. Ohio's rule lists Russian olive. The buckthorn page and the Russian olive page give the field tests. These are usually found in thickets along woodland edges rather than as single yard trees.

Black locust is the reminder that "invasive" depends on place. It is native to the eastern US, yet Minnesota lists it as a Restricted noxious weed. The same happens in reverse: Minnesota added European rowan to its Specially Regulated list in 2026, with a three-year phase-out before its sale is prohibited.

Using a photo

A photo is useful for the first step, putting a name on the tree. Tree Identifier names a plant from one photo, and Norway maple and mimosa are among the species in its Collection. Photograph a whole leaf flat, plus the leaflet base for tree of heaven or a snapped leaf stalk for Norway maple. The app shows no confidence score or list of alternatives, so confirm the result with the field test in the table, and ask follow-up questions, such as how chinaberry differs from a native ash, in the chat under the result. The app does not know your state's current law: for removal rules, ask your state department of agriculture or extension office.