Paul Wray
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Tree of Heaven
Ailanthus altissima
Origin: Central China
Background
Introduced by a Pennsylvania gardener in 1748 and into
California by immigrants during the gold rush years, Tree
of Heaven, also called stinking sumac, was available
commercially by 1840.
Distribution and Ecological Threat
Widely distributed across the United States, Tree of
Heaven occurs in 42 states, from Maine to Florida and west
to California. It is an extremely common tree in urban
areas where it can cause damage to sewers and structures
but poses a greater environmental threat because of its
invasiveness in cultivated fields and natural habitats. A
prolific seeder, Tree of Heaven grows vigorously,
establishing dense stands that displace native plants. It
produces chemicals that kill or prevent other plants from
growing in its vicinity.
Britt Slattery, USFWS
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Description and Biology
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Plant: a rapidly growing, deciduous tree in the mostly
tropical quassia family (Simaroubaceae). Mature trees
can reach 80 feet or more in height. Ailanthus has
smooth stems with pale gray bark, and twigs that are
light chestnut brown, especially in the dormant season.
Tree of Heaven is dioecious, meaning plants are either
male or female. The wood of Ailanthus is soft, weak,
coarse-grained and creamy white to light brown in
color. All parts of the tree, especially the flowers,
have a strong, offensive odor, which some have likened
to cat urine or rotting peanuts or cashews.
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Leaves: large compound leaves, 1 to 4 feet in length,
composed of 11 to 25 smaller leaflets and alternate
along the stems. Each leaflet has one to several
glandular teeth near the base.
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Flowers, fruits and seeds: large clusters of small
greenish flowers are produced during June; in the late
summer, female trees produce flat, twisted, papery
fruits called samaras that may remain on the trees for
long periods of time; an individual tree can produce up
to 325,000 seeds per year.
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Spreads: reproduces by seed and by vigorous
re-sprouting, especially in response to injury such as
cutting or breaking.
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Look-alikes: staghorn sumac (Rhus typhina), ash
(Fraxinus species) and black walnut (Juglans
nigra). The sumac has fuzzy, reddish-brown leaves
and stems. All ash species have opposite leaves. Black
walnut leaves are toothed, large green fruits fall from
the tree.
Prevention and Control
Correct identification of Tree of Heaven is essential.
Native shrubs are often confused with it. Elimination of
Ailanthus requires diligence, due to its abundant seed
production, high seed germination rate and vigorous
vegetative reproduction. Targeting large female trees for
control will help reduce spread by seed. Young seedlings
may be pulled or dug up, preferably when soil is moist.
Care must be taken to remove the entire plant including
all roots and fragments as these will almost certainly
re-grow. Extensive research has been conducted on
herbicidal methods of control for Tree of Heaven and
include leaf, bark and cut stem applications.
Native Alternatives
box elder (Acer negundo)
Britt Slattery, USFWS
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smooth sumac (Rhus glabra)
Chris Miller, NRCS
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black walnut (Juglans nigra)
Dennis Woodland, UWI
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green or white ash
(Fraxinus pennsylvanica or
americana)
Kitty Kohout, UWI
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fringetree (Chionanthus
virginicus)
R. Harrison Wiegand
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staghorn sumac (Rhus typhina)
R. Harrison Wiegand
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