Tree of heaven - the threat | Minnesota Department of Agriculture

Tree of Heaven parent plants can produce suckers from their roots up to 90 feet away. Photo by Chuck Bargeron, University of Georgia, Bugwood.org.
Tree of heaven produces flat, twisted, winged fruits called samaras, which hang in long clusters. Photo by Chuck Bargeron, University of Georgia, Bugwood.org.
Young seedlings grow leaves with many small leaflets arranged along a central stem early on. Photo by Chuck Bargeron, University of Georgia, Bugwood.org.
The flowers of tree of heaven are small, yellowish-green, and grow in large, showy clusters at the ends of the branches. Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org.
Bark on mature trees is textured and gray. Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org.

Tree of heaven has caused both environmental and economic damages in the United States. There have been very limited documented instances of tree of heaven in Minnesota. However, early detection of this invasive plant will be key to managing it. Here's why tree of heaven is so destructive:

Releases chemicals that prohibit other plants from growing, this displaces native plant species.
Decreases the value of timber by suppressing tree seedling germination of other plant species.
Reduces and degrades the habitats that support diverse plants and wildlife.
Produces root suckers and stump sprouts if cut.
Produces prolific seed and grows vigorously in riparian areas, disturbed areas, and natural areas.
Produces sap that may cause dermatitis when you come into contact with it.

Detect and Identify

Early detection and management are in key to preventing tree of heaven spreading into the landscape. The public can help by joining the citizen science project at UMN Extension. With more people trained to detect and identify tree of heaven infestations, they can be caught early and managed prior to causing problems.

Tree of heaven can be difficult to identify. Staghorn sumac, black walnut, and hickory are all native trees that resemble tree of heaven. The leaflet edges of these native trees all have teeth while those of tree of heaven are smooth.

Specific characteristics of tree of heaven:

Large tree that can reach 80 feet tall.
Bark is smooth and brownish-green when young, eventually turning light brown to gray, resembling the skin of a cantaloupe.
Leaves have a central stem in which leaflets are attached to each side - called pinnately compound. One leaf can be 1-4 feet long with 10-40 leaflets. Leaf edges are smooth.
When crushed, leaves and all plant parts give a strong, offensive odor.
Twigs have V- or heart-shaped leaf scars, and when the twigs are broken, the pith is spongy.
Seeds are 1-2-inch-long wings, called samaras. Samaras are in clusters and persist through the winter.

Tree of heaven grows in a variety of conditions:

Full and part sun
Fertile and dry soil
Riparian and disturbed areas
Railways and forest openings

Tree of heaven colonizes quickly in disturbed areas and forest openings.

Report and Manage

Early detection is key to successful management. You can help by detecting and reporting possible tree of heaven infestations.

1. Use or online reporting service Report a Pest

2. Email reportapest@state.mn.us

3. Call 1-888-545-6684

Please take detailed photos of the plant, and take note of the specific location. Take precautions when handling plants by wearing gloves.

After your report submission you can expect the following:

1. MDA staff may contact you for more information to make an accurate identification of the plant.

2. If the report is positive, the tree or infestation will be mapped.

3. The MDA will work with private landowners and local governments on controlling infestations if feasible.

Management recommendations will be site specific, but these are standard considerations:

Do not purchase and/or plant tree of heaven.
Cutting or mowing are ineffective because these actions stimulate tree of heaven to produce large amounts of stump sprouts and root suckers.
Cut stump herbicide applications are ineffective.
A foliar herbicide treatment in mid- to -late summer can be effective.
Basal bark herbicide applications can be effective.
Hand pulling seedlings may be effective when soil is moist, and the entire root system is removed. Small root fragments can generate new shoots.
Repeated treatments and monitoring will be necessary to successfully eradicate tree of heaven.