A tree growing along your fence may have arrived without anyone planting it. Seeds can travel into garden beds and woodland edges, while some trees send up new shoots from their roots. Identifying that growth helps you understand what is spreading on your property.
Unfamiliar growth can be easy to overlook when it blends into an established landscape. A young tree may resemble one you recognize, and flowers or seeds that make identification easier may appear only briefly. That uncertainty makes it worth learning more about the tree before deciding whether to keep it or have it removed.
What Makes a Tree Invasive?
An invasive tree is a nonnative species that spreads and causes harm, such as crowding out native plants. Fast growth, messy fruit, or spreading roots alone do not make a tree invasive.
The effects can extend beyond a yard when seeds or root shoots establish in nearby natural areas.
Four Invasive Tree Species Found in Maryland
1. Callery Pear, Including Bradford Pear
Look for white flower clusters in early spring, often with an unpleasant smell, followed by glossy, oval to heart-shaped leaves. Small, firm, brownish fruits develop later. Bradford pear is one variety of Callery pear.
Birds spread its seeds into fields and woodland edges, where seedlings can form dense, thorny thickets. Check leaves and fruit as well as flowers; native flowering trees can look similar from a distance.
2. Norway Maple
Norway maple has broad leaves with five to seven pointed sections, called lobes. Its paired “helicopter” seeds have wings that spread in a nearly straight line. A freshly detached leaf stem can release milky white sap during the growing season.
Its leaves resemble native sugar maple leaves, making the seed shape and sap useful additional clues. In woodlands, its dense shade and competing roots can suppress native plants.
3. Tree-of-Heaven
Each long leaf is divided into smaller leaflets along a central stalk. The leaflet edges are mostly smooth, with small teeth near the base. Tiny raised glands sit underneath those teeth. Female trees produce hanging clusters of papery, winged seeds.
Tree-of-heaven spreads through seeds and root shoots and is a preferred host for spotted lanternflies. It resembles native sumacs and black walnut, so inspect the leaflet edges closely.
4. Princess Tree, Also Called Empress Tree
Look for large, velvety, heart-shaped leaves and pale purple, trumpet-shaped flowers that appear before the leaves in spring. Rounded, woody seed capsules turn brown and can remain on the branches through winter.
Wind carries its seeds into forest clearings, woodland edges, and other disturbed areas. Its leaves can resemble catalpa leaves, but catalpa produces long, slender seed pods rather than rounded capsules.
What to Do if You Suspect an Invasive Tree
Confirm the identification before cutting or treating it. Photograph the whole tree and any bark, leaves, flowers, or seeds you can safely see from the ground. Include both sides of a leaf if one is within easy reach. You do not need every feature photographed; an arborist can help when identification remains unclear.
The next step depends on the species and its size. Cutting down tree-of-heaven can trigger new shoots from surviving roots, which is why tree-of-heaven requires planning.
Once you know what is growing, check nearby beds and fence lines for additional seedlings or root shoots. Finding new growth early makes it easier to plan a response without mistakenly removing similar-looking native trees.