Ronald P. Overton
Boxelder (Acer negundo) is one of the most widespread and best known of the maples. Its other common names include ashleaf maple, boxelder maple, Manitoba maple, California boxelder, and western boxelder. Best development of the species is in the bottom-land hardwood stands in the lower Ohio and Mississippi River valleys, although it is of limited commercial importance there. Its greatest value may be in shelterbelt and street plantings in the Great Plains and the West, where it is used because of its drought and cold tolerance.
The common name, “boxelder,” refers to the resemblance of its leaves to elder (Sambucus) and the use of the soft wood for box making. “Ashleaf maple,” refers to the resemblance to ash (Fraxinus).
Boxelder is a small, deciduous, fast-growing, short-lived tree growing to 20 m tall, with a broad rounded crown. It often branches low into multiple trunks, which may grow almost parallel to the ground, and can form dense thickets. The bark is light brown-gray with shallow fissures, becoming deeply furrowed. Twigs are slender, shiny green, usually glabrous (without hairs), and often have a whitish to pink or violet waxy coating (glaucous) when young. The leaves are opposite, pinnately compound with 3 to 9 leaflets, long-pointed, coarsely toothed and often shallowly lobed. The flowers are yellow-green, about 5 mm long; the species is generally dioecious (functional male and female flowers occur on separate trees; Wagner 1975; Fewless 2011). Fruits are long-stalked clusters of winged nutlets (samaras) in a pair, 2.5-4 cm long.
Boxelder is generally a tree of river bottoms and disturbed sites on heavy, wet or seasonally flooded soils, where it usually follows cottonwood and willow species in colonizing alluvial bottoms. Populations in native habitats have decreased because of clearing of bottomland forest for agriculture, but they have greatly increased in urban areas, where it readily colonizes disturbed sites due to its prolific seed production, wide dispersal, ease of germination, tolerance of cold, drought, and low-oxygen conditions, and fast growth on clay or heavy fill. It frequently grows along fencerows, railroad tracks, ditches, and abandoned lots (Michigan Flora Online 2011).
Boxelder was widely planted in the Great Plains as a shelterbelt tree—its shallow, fibrous root system helped reduce wind erosion and dust storms—but shelterbelts have largely been removed. It was also widely planted in the U.S. as a street tree, and ornamental cultivars have been developed (including forms with variegated leaves and without seeds).
It has been planted in Europe, Australia, and South America as a roadside, park, garden, and shelterbelt tree, and has naturalized widely in disturbed areas and along riverbanks. It is considered invasive in Poland, Germany, Austria, Russia, Latvia, and Lithuania (Mędrzycki 2011), as well as Australia, New Zealand, China, and Chile (USFS 2011).
Boxelder is sometimes confused with poison ivy (Toxicodendron radicans), because its compound leaves often have three leaflets. A key distinction is that boxelder leaves are opposite rather than alternate.
The boxelder bug (Boisea trivittata, family Rhopalidae) commonly associates with boxelder. The insects cause little damage to the trees, but are considered a pest species because they invade human habitation, often in large numbers, with the onset of cold weather (Hahn and Ascerno 2007).
General: Maple Family (Aceraceae): Boxelder is a native tree growing to 20 m tall, with broad rounded crown, usually developing a shallow, fibrous root system; bark light gray-brown with shallow fissures, becoming deeply furrowed; twigs slender, shiny green, usually glabrous but sometimes hairy. The leaves are opposite, 13-20 cm long, pinnately compound with 3(-5 or more) leaflets 5-10 cm long and 3-6 cm wide, long-pointed, coarsely toothed and often shallowly lobed. The flowers are yellow-green, about 5 mm long, the male (staminate) flowers fascicled, the female (pistillate) flowers in drooping racemes; most trees are either male or female (the species is essentially dioecious), but bisexual flowers occur on a few trees (technically polygamo-dioecious). Fruits are winged nutlets (samaras) in a pair, 2.5-4 cm long, clustered on long stalks. The common name refers to the resemblance of leaves to those of ash (Fraxinus). Boxelder, its other often used common name, refers to a resemblance to elder (Sambucus) and the use of the soft wood for box making.
Boxelder is unusual among American maples in having compound leaves. Apart from the opposite leaves, seedlings and young saplings of Boxelder bear a remarkable resemblance to poison ivy (Toxicodendron radicans) and are often mistaken for it by beginning naturalists.
Variation within the species:
Substantial variation occurs over the range of the species; numerous forms and varieties have been described, but only six varieties currently recognized (in some treatments, for example, see McGregor 1986). These are primarily distinguished by coloration of the branches, twig and fruit pubescence, and leaflet number.
Var. arizonicum Sarg. – Arizona and New Mexico
Var. californicum (Torr. & Gray) Sarg. – California
Var. interius (Britt.) Sarg. – midwest US into the western states
Var. negundo – the eastern half of the US, with naturalized western outlyers
Var. texanum Pax – south-central US
Var. violaceum (Kirchn.) Jaeger – north-central US and most of Canada
Range and Habitat in Illinois
Regularity: Regularly occurring
Regularity: Regularly occurring
most of the contiguous United States. Its range extends from New Jersey
and central New York west through extreme southern Ontario, central
Michigan, northern Minnesota, central Manitoba, central Saskatchewan,
southern Alberta and central Montana, eastern Wyoming, Utah, and
California; and south to southern Texas and central Florida. It is also
local in New Hampshire, Vermont, Massachusetts, Connecticut, Idaho, and
Nevada. Boxelder has been naturalized in Maine, southern Quebec, New
Brunswick, Nova Scotia, Prince Edward Island, and in southeastern
Washington and eastern Oregon. Varieties of boxelder occur in the
mountains of Mexico (Nuevo Leon, San Luis Potosi, and south to
Chihuahua) and in Guatemala .
General distribution by variety is as follows :
var. negundo -- eastern United States and introduced to eastern
Washington and Oregon
var. interior -- Rocky Mountains to Arizona and Canada
var. violaceum -- northeastern United States and northern Great Plains
var. texanum -- western Missouri, eastern Kansas and throughout the
var. californicum -- California
var. arizonicum -- Arizona and New Mexico
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
1 Northern Pacific Border
3 Southern Pacific Border
6 Upper Basin and Range
8 Northern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
Occurrence in North America
IL IN IA KS KY LA ME MD MA MI
MN MS MO MT NE NV NH NJ NM NC
NY ND OH OR PA SC SD TN TX UT
VA WA WV WI WY AB MB NS ON PE
PQ SK MEXICO
- Native range of boxelder
Boxelder is natively a tree of river bottoms and disturbed sites on heavy, wet soils, often seasonally flooded (up to 30 days). It is one of the most common bottomland trees throughout its range, usually following the pioneer species of cottonwood and willow in colonizing alluvial bottoms, then growing with silver and red maples, American elm, American sycamore, and sweetgum. Populations in native habitats have decreased because of clearing of bottomland forest for agriculture, but they have greatly increased in urban areas. Success of the species on disturbed urban sites owes to its prolific seed production and wide dispersal, ease of germination, tolerance of low oxygen conditions, and fast growth on clay or heavy fill. Boxelder also is found as a pioneer species on disturbed upland sites where a seed source is nearby.
Flowering: March-May (with or just before the leaves), fruiting: August-October. The flowers are wind pollinated but also visited by bees.
Boxelder is the most widely distributed of all American maples – its native range extends from the east coast of the U.S. to California, and from Alberta to southern Mexico and Guatemala. The range is relatively continuous in the eastern U.S., but broken into small areas in the West and toward Central America. It has become naturalized in areas far outside of its native range, including Europe. It is not known from northern North America. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.
Boxelder is a native deciduous small to large tree with an irregular
form. The trunk often divides near the ground into a few long,
spreading, rather crooked limbs, which branch irregularly to support a
broad, uneven crown. When growing among other trees, boxelder forms a
high, open crown, with the undivided portion of the trunk much longer
and usually straighter than that of an open-grown tree . This
variable-sized tree may reach 70 feet (21 m) in height and 3 feet (0.92
m) in diameter but is more often medium sized, from 40 to 50 feet (12-15
m) high and from 1 to 2 feet (0.3-0.6 m) in diameter . Boxelder may
also appear as a large shrub , and in upland soil on the Great
Plains this tree is usually only about 25 feet (8 m) high with low,
crooked branches .
Boxelder has a fast growth rate [33,41] and a short life span ; it
typically lives for 75 years, with 100 years maximum longevity .
Growth is rapid when young; long, smooth, green annual shoots extend 2
feet (0.6 m) or more in a year. At maturity growth slows and brittle
trunks and limbs shatter; old trunks frequently put out clusters of
sprouts and sometimes develop large burls .
A drought-tolerant tree once established, boxelder's roots are shallow
and spreading, except on deep soils [41,46]. The bark is light grey and
smooth but becomes furrowed into narrow, firm ridges and darkens with
age. Twigs are stout, light green to purplish or brownish with a
polished look or are often covered with a whitish bloom that is easily
rubbed off. The blunt buds are 0.125 to 0.25 inch (2-5 mm) long with
one or two pairs of scales and are coated with fine white hairs .
Boxelder is the only maple with divided leaves. The three to seven
leaflets are from 6 to 15 inches (15-38 cm) long, light green above and
greyish green below, usually without hairs. The leaflets are shallowly
lobed or coarsely toothed . This completely dioecious tree has pale
green male and female flowers with a strongly pronounced reduction of
flower parts, and contains no rudimentary parts of the opposite sex.
Male flowers are on slender stalks in loose clusters, and female flowers
are arranged along a separate stem [27,54].
The fruit is composed of two fused, winged samaras which eventually
separate upon shedding. The angle separating the two wings is less than
60 degrees . The samaras, about 1.5 inches (4 cm) long, hang in
long chains on slender stalks, mature in autumn, and remain on the tree
well into the winter . Each contains a single seed without an
endosperm . Seeds are 2 to 3 times as long as they are wide and are
Many ecotypes of this species occur. Varieties are distinguished by the
morphological characteristics of glaucousness, pubescence, or color of
the branches and/or samaras.
Range and Habitat in Illinois
Key Plant Community Associations
in the Great Plains. It is associated with the following overstory
dominants: green ash (Fraxinus pennsylvanica), narrowleaf cottonwood
(Populus angustifolia), plains cottonwood (P. sargentii), aspen (P.
tremuloides), willow (Salix spp.), and bur oak (Quercus macrocarpa). In
Arizona and New Mexico, boxelder is the overstory dominant in several
high elevation riparian forests. In much of this species' range there
are no described plant communities.
Published classification schemes listing boxelder as a member of various
community types (cts), habitat types (hts), or dominance types (dts) are
Location Classification Authority
AZ, NM riparian cts Szaro 1990
MT riparian dts Hansen & others 1988
MT, se ID riparian cts Padgett & others 1989
sw NM riparian hts Medina 1986
sc OK bottomland cts Petranka & Holland 1980
SD,ND: Custer NF general veg. hts Hansen & Hoffman 1988
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K011 Western ponderosa forest
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K018 Pine - Douglas-fir forest
K019 Arizona pine forest
K023 Juniper - pinyon woodland
K025 Alder - ash forest
K037 Mountain-mahogany - oak scrub
K038 Great Basin sagebrush
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K067 Wheatgrass - bluestem - needlegrass
K070 Sandsage - bluestem prairie
K074 Bluestem prairie
K081 Oak savanna
K098 Northern floodplain forest
K099 Maple - basswood forest
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
More info for the term: shrub
FRES15 Oak - hickory
FRES16 Oak - gum - cypress
FRES17 Elm - ash - cottonwood
FRES18 Maple - beech - birch
FRES19 Aspen - birch
FRES21 Ponderosa pine
FRES28 Western hardwoods
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
FRES36 Mountain grasslands
FRES38 Plains grasslands
floodplains, and in low-lying wet places where its shallow root system
can find abundant moisture . Hardy to extremes of climate ,
boxelder is drought tolerant once well established and can also
withstand short periods of flooding .
Soils: This species is able to tolerate a wide variety of soils but
shows a strong preference for well-drained soils . Although
boxelder will grow on soils from gravel to clay, it grows best on deep,
sandy loam, loam, or clay loam soils with a medium to rocky texture and
a pH of 6.5 to 7.5 .
Associates: Throughout its range, boxelder is most often associated
with various species of cottonwood (Populus spp.) and willow (Salix
spp.). On the northern Great Plains, boxelder will generally outlive
cottonwood and willow to become an associate in American elm (Ulmus
americana), hackberry (Celtis occidentalis), mulberry (Morus spp.), and
green ash communities . In the central Great Plains and in the
eastern United States, boxelder occurs with elms (Ulmus spp.), sugar
maple (Acer rubrum), basswood (Tilia spp.), and ashes (Fraxinus spp.),
which eventually replace boxelder in the overstory along with other more
durable and shade-tolerant species [31,51]. At higher elevations on the
Utah plateaus, boxelder occurs in the riparian zone with water birch
(Betula occidentalis), narrowleaf cottonwood (Populus angustifolia),
willows, and blue spruce (Picea pungens) . In New Mexico and
Arizona, scattered along streambeds in riparian forests at higher
elevations, boxelder is a typical canopy dominant with Arizona alder
(Alnus oblongifolia) and coyote willow (Salix exigua) .
Elevation: The elevational ranges for boxelder in several states
are as follows [9,29,31,35,36,46]:
AZ from 4,450 to 8,000 feet (1,356-2,438 m)
CO 4,500 to 7,870 feet (1,372-2,400 m)
MT 2,240 to 4,500 feet (680-1,372 m)
NE 2,600 to 4,500 feet (792-1,372 m)
NM 6,350 to 6,775 feet (1,935-2,065 m)
ND 2,310 to 3,840 feet (704-1,170 m)
SD 3,000 to 3,500 feet (914-1,067 m)
UT 4,000 to 10,000 feet (1,219-3,048 m)
WY 3,500 to 7,700 feet (1,067-2,347 m)
Mexico 4,600 to 5,947 feet (1,400-1,800 m)
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
42 Bur oak
46 Eastern redcedar
61 River birch - sycamore
62 Silver maple - American elm
87 Sweetgum - yellow poplar
93 Sugarberry - American elm - green ash
94 Sycamore - sweetgum - American elm
95 Black willow
235 Cottonwood - willow
236 Bur oak
Soils and Topography
Habitat & Distribution
Flowering in Boxelder is in early spring and large quantities of seed are produced each year, beginning on trees 8-11 years old. The seeds ripen in autumn, fall continuously from autumn until spring, and are light, large-winged, and widely wind-dispersed. They over-winter and germinate the following spring. Best germination follows stratification for 60-90 days at 33 F.
Boxelder seeds germinate in shade or full sun but seedlings begin to die off after 1-2 years unless openings are formed. Successful seedbeds vary greatly. Trees are fast growing, producing up to 1-inch diameter annual growth for the first 15-20 years. Early growth is best in full sun but tolerant of partial shade. Young trees commonly produce stump and root sprouts. Average longevity is about 60 years; maximum longevity is rarely more than 100.
Flower-Visiting Insects of Box Elder in Illinois
(this small tree is normally wind-pollinated; bees collect pollen, while the beetle feeds on pollen; observations are from Robertson, Krombein et al., and Lisberg & Young)
Apidae (Apinae): Apis mellifera cp fq (Rb)
Andrenidae (Andreninae): Andrena forbesii cp (Kr), Andrena imitatrix imitatrix cp (Kr)
Mordellidae: Mordellistena cervicalis (LY)
Foodplant / parasite
fruitbody of Agrocybe cylindracea parasitises branch of Acer negundo
Other: minor host/prey
Foodplant / saprobe
gregarious, long concealed by epidermis pycnidium of Phomopsis anamorph of Cryptodiaporthe lebiseyi is saprobic on branch of Acer negundo
Remarks: season: 4
Foodplant / saprobe
immersed, multilocular, c. 1mm diam. stroma of Cytospora coelomycetous anamorph of Cytospora annulata is saprobic on dead, locally stained branch of Acer negundo
Foodplant / saprobe
fruitbody of Rigidoporus ulmarius is saprobic on dead, white-rotted stump of Acer negundo
Foodplant / parasite
Sawadaea bicornis parasitises Acer negundo
Associated Forest Cover
42 Bur Oak
61 River Birch-Sycamore
62 Silver Maple-American Elm
93 Sugarberry-American Elm-Green Ash
94 Sycamore-Sweetgum-American Elm
95 Black willow
236 Bur Oak
Other associates in the eastern United States include red maple (Acer rubrum), hackberry (Celtis occidentalis), slippery elm (Ulmus rubra), black walnut (Juglans nigra), basswood (Tilia americana), black cherry (Prunus serotina), blackgum (Nyssa sylvatica), pecan (Carya illinoensis), Nuttall, water, willow, and overcup oak (Quercus nuttallii, Q. nigra, Q. phellos, and Q. lyrata), persimmon (Diospyros virginiana), and baldcypress (Taxodium distichum). In the Plains region, boxelder appears with green ash (Fraxinus pennsylvanica), bur oak (Quercus macrocarpa), plains cottonwood (Populus deltoides var. occidentalis), willow (Salix spp.), and hackberry. In the Rocky Mountains and the Colorado Plateau, associates include several species of willow and cottonwood, netleaf hackberry (Celtis reticulata), and Arizona sycamore (Platanus wrightii).
Diseases and Parasites
Verticillium wilt (Verticillium albo-atrum) is the only notable killing disease of boxelder. The species is also susceptible to a stem canker caused by Eutypella parasitica.
A red stain in the wood of living trees caused by Fusarium reticulatum var. negundinis apparently is specific to boxelder. The stain regularly is associated with Cerambycid beetles and the galleries of other insects, but itself does no damage to the wood (14).
Insect damage to boxelder is relatively unimportant, but a number of leaf-feeding and scale insects and borers attack it (1). The boxelder bug, Leptocoris trivittatus is a common associate of boxelder throughout most of its range. The nymphs feed mainly on pistillate trees in leaves, fruits, and soft seeds. Although the trees are not greatly damaged, the insect's habits of invading houses in large numbers with the onset of cold weather makes it an important pest. The boxelder aphid, Periphyllus negundinis, and the boxelder gall midge, Contarinia negundifolia, are also common. Other leaf feeders include the Asiatic garden beetle, Maladera castanea, the greenstriped mapleworm, Anisota rubicunda, a leaf-roller, Archips negundana, and the boxelder leafroller, Caloptilia negundella. The scale insects include cottony maple scale, Pulvinaria innumerabilis, and terrapin scale, Mesolecanium nigrofasciatum. Borers include the boxelder twig borer, Proteoteras willingana, and the flatheaded apple tree borer, Chrysobothris femorata.
Ice and wind damage is common in older trees (11) and boxelder is quite susceptible to fire and mechanical damage due to its thin bark.
Boxelder is highly sensitive to 2,4-D. In the northern Great Plains, drift from agricultural spraying operations produced distorted, blighted foliage up to 16 km (10 mi) from the source (20).
Broad-scale Impacts of Plant Response to Fire
The Research Project Summary Effects of surface fires in a mixed red and
eastern white pine stand in Michigan provides information on prescribed
fire and postfire response of plant community species, including boxelder,
that was not available when this species review was written.
Plant Response to Fire
Boxelder most likely reestablishes following fire via wind-dispersed
seeds [31,51]. It may also sprout from the roots, the root collar, or
stump if girdled or top-killed by fire.
off-site colonizer species;seed transported by wind;postfire years 1&2
off-site colonizer species;seed transported by animals;post-fire years 1&2
survivor species; on-site surviving root crown or caudex (possible)
Boxelder grows on moist bottomland sites which are seldom subject to
burning. This thin-barked species is injured by fire , but how it
regenerates following fire is not known. Boxelder produces large yearly
crops of wind-dispersed seeds which germinate on a wide variety of
soils; this is most likely boxelder's primary fire survival strategy.
This tree also sprouts from the exposed roots, root crown, or stump
following top-killing mechanical damage [1,13,19,38], and it is likely
that boxelder would sprout following fire severe enough to girdle or
top-kill the adult tree.
More info for the terms: climax, codominant
Boxelder occurs in a variety of forest types ranging from early to late
seral, making its successional position difficult to determine. It is
moderately shade tolerant but does not reproduce in its own shade. It
usually establishes under pioneering species such as cottonwood and
willow, particularly in the northern Great Plains , and is then
followed by more shade-tolerant, climax species . In Arizona and
New Mexico, boxelder is a dominant or codominant overstory species in
several high-elevation riparian communities .
Boxelder reproduces both sexually and asexually . Large seed crops
are produced each year . Seeds persist through the winter; they are
dispersed by wind or by birds and squirrels [31,51]. Wind will carry
these winged seeds up to 100 yards across a snow surface .
Boxelder establishes by seed under a wide range of conditions:
immediately after disturbance on moist disturbed soil , along
riverbanks , and in areas with heavy cover and medium to heavy
competition . In southern Illinois, Hosner and Minckler 
reported reproduction of boxelder on areas with light, medium, and heavy
light duff med duff heavy duff
(over 0.5 in) (0.5 to 2 in) (over 2 in)
No. of 1- and
2-yr-old seedlings 121 90 35
Vegetative reproduction is also common on damaged plants of this
species. New shoots will appear on exposed or injured roots .
After the extreme drought condition of the 1930's in the Great Plains,
during which nearly all boxelder trees in shelterbelts 30 years or older
died back to the ground, many trees recovered by producing root sprouts,
forming a dense hedge or undergrowth . In shelterbelts of the
northern Great Plains, boxelder has a dense growing habit resulting from
the plant suckering at the root collar . Seven years after timber
harvest in a South Carolina bottomland, sprouts from boxelder stumps
greater than 20 inches (51 cm) in diameter were reported to be dying or
losing vigor . Although this species will produce abundant sprouts
after disturbance, the primary method of reproduction is through seed,
due to the quantity produced each year and the facility of its
Growth Form (according to Raunkiær Life-form classification)
Immediate Effect of Fire
Reaction to Competition- In the area of its best development, the lower Ohio and Mississippi River valleys, boxelder usually follows the pioneer species of cottonwood and willow in colonizing new ground in alluvial bottoms. In some instances it is a pioneer species in the invasion of old fields (16). Boxelder may persist into the oak-hickory type but then begins to be eliminated, probably due to shading (18). The species is generally classed as tolerant of shade, although less so than the other soft maples (13).
Life History and Behavior
Boxelder flowers from March through May with or before the appearance of
the leaves. The fruit, a winged samara, ripens from September through
October and is dispersed from September through March [39,50,53].
Boxelder's leaves turn a dull yellow color in the autumn and drop
throughout the fall and winter .
Seed Production and Dissemination
Seedling Development- Boxelder is capable of establishing itself on a variety of seedbeds. On southern Illinois bottom lands, it is among the most abundant species seeding in under cottonwood-willow and "soft" hardwood stands and invading old fields. On these sites, overstory density is apparently not a factor in early germination and survival, but seedlings begin to die off after 1 or 2 years unless openings are provided. The 1- and 2-year-old boxelder seedlings are also abundant in areas of ground vegetation ranging from light to heavy and in hardwood litter as much as 5 cm (2 in) deep (16).
Methods of collecting, handling, storing, and testing boxelder seeds have been described (3,4,26). Germination is epigeal.
Flowering and Fruiting
Growth and Yield
Because boxelder usually appears in mixed stands and has limited commercial value, no information is available about its potential yield. Equations are available, however, to predict volume of boxelder stems, and green and dry weights of stems, limbs, and leaves (24). After trees reach 15 cm (5.9 in) in d.b.h., the proportion of aboveground green components is relatively constant, with bole wood, 63 percent; bole bark, 8 percent; limbs, 22 percent; and leaves, 7 percent.
Molecular Biology and Genetics
Some 8 to 14 varieties and forms have been described for boxelder, several relating to variegated patterns of the foliage or some other morphological character (2,17,21,23,28). At least two varieties appear to be confined to a definite geographic range: var. arizonicum Sarg. to central and southern Arizona and New Mexico and var. californicum (Torr. and Gray) Sarg. to the Central Valley, Coast Range, and San Bernardino Mountains of California (23).
Barcode data: Acer negundo
Statistics of barcoding coverage: Acer negundo
Public Records: 12
Specimens with Barcodes: 18
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status, and wetland indicator values.
Boxelder is susceptible to mechanical damage by livestock in northern
Great Plains wooded draws . This tree is also easily storm damaged;
its weak branches often break off in the wind, but the trunk is wind
Boxelder is easily injured by heart rot, fire, and insects. It is often
infested with boxelder bugs which feed on the tree but rarely kill it
Cultivars, improved and selected materials (and area of origin)
Boxelder is available at most nurseries within it distribution.
Boxelder is tolerant to stressful sites and requires little special care, but it is relatively short-lived and the branches of older trees are susceptible to ice and wind damage. Boxelder is highly sensitive to 2,4-D and also is susceptible to fire and mechanical damage because of its thin bark.
The boxelder bug is a common associate of boxelder
throughout most of its range. The nymphs feed mainly on female (pistillate) trees in leaves, fruits, and soft seeds. The trees are not greatly damaged but the insects sometimes invade human habitation in large numbers with the onset of cold weather.
Relevance to Humans and Ecosystems
Uses: Cultivated ornamental
Other uses and values
Boxelder, first cultivated in 1688 , is often held in low regard as
an ornamental tree in cities. Its limbs are brittle and break easily;
its trunk is susceptible to rot and infested with boxelder bugs, which
make their way into houses with the arrival of cold weather. The leaves
turn a dull yellow and fall untidily over a long period, as do the
winged seeds, giving this species the reputation of being a "dirty tree"
[27,31,52]. However, because of its fast growth and drought and cold
hardiness, boxelder is popular in rural communities for street and
ornamental plantings; and for shelterbelts.
Boxelder's abundant sap contains a large proportion of sugar as well as
mucilaginous and demulcent properties, and can be made into a pleasant
beverage . The Plains Indians used the sap as a source of syrup,
and it is still used today, but the product is not as sweet as sugar
maple syrup .
Value for rehabilitation of disturbed sites
acidic soils; it is not recommended for use in rehabilitation of
disturbed sites. This tree's potential for erosion control and for
long-term revegetation is low to medium .
In California, Arizona, and parts of Nevada and New Mexico, boxelder is
one of many native species used for revegetating flood control basins to
provide quality wildlife habitat . In the southeastern United
States where soil moisture (or inundation) is likely to be excessive for
several weeks at a time, boxelder is one of the favored flood-tolerant
species recommended for recreation plantings.
Boxelder is propagated by seed. Guides for seed collection, treatment,
and cultivation are available [7,39,44,53].
Boxelder provides valuable cover for wildlife and livestock, especially
in the Great Plains region where quality cover is often lacking. The
degree to which this species provides environmental protection during
one or more seasons for wildlife species is as follows :
UT CO WY MT ND
Elk ---- poor ---- poor ----
Mule deer fair ---- good good fair
White-tailed deer ---- ---- good good good
Pronghorn poor ---- poor ---- poor
Upland game birds fair ---- good good ----
Waterfowl poor ---- poor ---- ----
Small nongame birds good good good good ----
Small mammals fair good fair fair ----
Importance to Livestock and Wildlife
wildlife species and protect livestock from temperature extremes in
summer and winter. Many species of birds and squirrels feed on the
seeds of boxelder [23,40,46]. Mule deer and white-tailed deer use it in
the fall as a browse species of secondary importance . This tree
may be poisonous to livestock .
Wood Products Value
Boxelder is not a desired timber species because its wood is light,
soft, close grained, and low in strength [27,41,45]. The wood is used
locally for boxes and rough construction , and is used occasionally
for cheap furniture and woodenware. Boxelder was once used for posts,
fencing, and fuel but the soft, spongy wood generally makes poor
value, poor protein value, and suspected toxicity .
UT WY MT ND
Cattle poor poor poor poor
Sheep poor poor poor poor
Horses poor poor poor poor
Elk poor fair ---- ----
Mule deer poor good poor poor
White-tailed deer ---- fair poor poor
Pronghorn poor poor ---- poor
Upland game birds fair fair ---- ----
Waterfowl poor fair ---- ----
Small nongame birds fair fair fair ----
Small mammals fair fair ---- ----
Seeds and other portions of boxelder are utilized by many species of birds and mammals as food (19). Because of the species delayed seeding habit, some seeds are available throughout most of the winter. The sap of boxelder has been used to a limited extent for syrup (9).
The wood of Boxelder is light, soft and weak, and of low commercial value. It is used for pulp and rough lumber, usually mixed with other bottomland species, and has been used for boxes and crates, low-quality furniture, and interior finishing.
Boxelder produces sap high in sugar content and can be used to produce syrup sometimes called "mountain molasses." Native Americans used the cambium for food, boiled down the sap for syrup and candy, and made a tea from the inner bark to induce vomiting. The new branches were used to make charcoal for ceremonial painting.
The trees are useful for quick growth in naturalized riparian plantings, but they are short-lived and disease-prone. The species was once planted in the U.S. as a street tree and ornamental cultivars have been developed (including forms with red fall color, variously variegated leaves, and without seeds). It is not now commonly planted in the U.S., where its removal is sometimes more of a challenge. The quick growth of this species, however, and its tolerance to urban conditions, allows it to contribute to shade and rapid re-greening in disturbed city sites, particularly in the Great Plains and the West, because of its drought and cold tolerance. Boxelder can be used temporarily until replaced by slower growing but longer lasting trees.
Boxelder was once widely planted in shelterbelts in the Great Plains to reduce wind erosion and dust storms, but these shelterbelts have largely been removed. Its fibrous root system and prolific seeding habit make it valuable for erosion control in some parts of the world. The seeds are important winter food for birds and small mammals, deer browse young plants.
Acer negundo is a species of maple native to North America. Box elder, boxelder maple, ash-leaved Maple, and maple ash are its most common names in the United States; in Britain and Ireland it is also known as ashleaf maple.
Other variant names, some of which are regional, include: In Canada it is commonly known as Manitoba Maple and occasionally as Elf Maple. Other names include Ash Maple, Ash-leaf Maple, Black Ash, California Boxelder, Cutleaf Maple, Cut-leaved Maple, Negundo Maple, Red River Maple, Stinking Ash, Sugar Ash, Three-leaved Maple, and Western Boxelder. In Russia it is called American Maple (Russian: американский клён) as well as Ash-leaf Maple (Russian: клён ясенелистный).
Acer negundo is a small, usually fast-growing and fairly short-lived tree that grows up to 10–25 metres (33–82 ft) tall, with a trunk diameter of 30–50 centimetres (12–20 in), rarely up to 1 metre (3.3 ft) diameter. It often has several trunks and can form impenetrable thickets.
The shoots are green, often with a whitish to pink or violet waxy coating when young. Branches are smooth, somewhat brittle, and tend to retain a fresh green colour rather than forming a bark of dead, protective tissue. The bark on its trunks is pale gray or light brown, deeply cleft into broad ridges, and scaly.
Unlike most other maples (which usually have simple, palmately lobed leaves), Acer negundo has pinnately compound leaves that usually have three to seven leaflets. Simple leaves are also occasionally present; technically, these are single-leaflet compound leaves. Although some other maples (such as Acer griseum, Acer mandshuricum and the closely related A. cissifolium) have trifoliate leaves, only A. negundo regularly displays more than three leaflets.
The leaflets are about 5–10 centimetres (2.0–3.9 in) long and 3–7 centimetres (1.2–2.8 in) wide with slightly serrate margins. Leaves have a translucent light green colour and turn yellow in the fall.
The flowers are small and appear in early spring on drooping racemes 10–20 centimetres (3.9–7.9 in) long. The fruits are paired samaras, each seed slender, 1–2 centimetres (0.39–0.79 in) long, with a 2–3 centimetres (0.79–1.18 in) incurved wing; they drop in autumn or they may persist through winter. Seeds are usually both prolific and fertile.
Unlike most other maples, A. negundo is fully dioecious and both a "male" and "female" tree are needed for either to reproduce.
- Winter buds: Terminal buds acute, an eighth of an inch long. Lateral buds obtuse. The inner scales enlarge when spring growth begins and often become an inch long before they fall.
- Flowers: April, before the leaves, yellow green; staminate flowers in clusters on slender hairy pedicels one and a half to two inches long. Pistillate flowers in narrow drooping racemes.
- Calyx: Yellow green; staminate flowers campanulate, five-lobed, hairy. Pistillate flowers smaller, five-parted; disk rudimentary.
- Corolla: Wanting.
- Stamens: Four to six, exserted; filaments slender, hairy; anthers linear, connective pointed.
- Pistil: Ovary hairy, borne on disk, partly enclosed by calyx, two-celled, wing-margined. Styles separate at base into two stigmatic lobes.
- Fruit: Maple keys, full size in early summer. Borne in drooping racemes, pedicels one to two inches long. Key an inch and a half to two inches long, nutlets diverging, wings straight or incurved. September. Seed half an inch long. Cotyledons, thin, narrow.
Indicative of its familiarity to many people over a large geographic range, A. negundo has numerous common names.
The names "Box Elder" and "Boxelder Maple" are based upon the similarity of its whitish wood to that of boxwood and the similarity of its pinnately compound leaves with those of some species of elder. This is the only North American maple with compound leaves.
Other common names are based upon this maple's similarity to ash, its preferred environment, its sugary sap, a description of its leaves, its binomial name, and so on. These names include (but are not limited to) Ash-, Cut-, or Three-leaf (or -leaved) Maple; Ash Maple; Sugar Ash; Negundo Maple; and River Maple.
Common names may also designate a particular subspecies. For example, a common name for A. negundo subsp. interius may be preceded by "Inland" (as in "Inland Boxelder Maple"). A common name for A. negundo subsp. californicum may be preceded by "California" or "Western".
Acer negundo is often discussed as comprising three subspecies, each of which was originally described as a separate species. These are:
- A. negundo subsp. negundo is the main variety and the type to which characteristics described in the article most universally apply. Its natural range is from the Atlantic Coast to the Rocky Mountains.
- A. negundo subsp. interius has more leaf serration than the main species and a more matte leaf surface. As the name interus indicates, its natural range of Saskatchewan to New Mexico is sandwiched between that of the other two subspecies.
- A. negundo subsp. californicum has larger leaves than the main species. Leaves also have a velvety texture which is essential to distinguish it from A. negundo subsp. negundo. It is found in parts of California and Arizona.
Some authors further subdivide subsp. negundo into a number of regional varieties but these intergrade and their maintenance as distinct taxa is disputed by many. Even the differences between recognized subspecies are probably a matter of gradient speciation
Finally, note that a few botanists treat Boxelder Maple as its own distinct genus (Negundo aceroides) but this is not widely accepted.
Although native to North America, it is considered an invasive species in some areas of that continent. It can quickly colonize both cultivated and uncultivated areas and the range is therefore expanding both in North America and elsewhere. In Europe where it was introduced in 1688 as a park tree it is able to spread quickly in places and is considered an invasive species in parts of Central Europe (Germany and the Czech Republic, middle Danube, Vistula river valley in Poland) where it can form mass growth in lowlands, disturbed areas and riparian biomes on calcareous soils. It has also become naturalized in eastern China and can be found in some of the cooler areas of the Australian continent where it is listed as a pest invasive species.
This species prefers bright sunlight. It often grows on flood plains and other disturbed areas with ample water supply, such as riparian habitats. Human influence has greatly favoured this species; it grows around houses and in hedges, as well as on disturbed ground and vacant lots.
Although its weak wood, irregular form, and prolific seeding might make it seem like a poor choice for a landscape tree, A. negundo is one of the most common maples in cultivation and many interesting cultivars have been developed, including:
- 'Auratum' - yellowish leaves with smooth undersides
- 'Aureomarginatum' - creamy yellow leaf margins
- 'Baron' - Hardier & seedless variety
- 'Elegans' - distinctively convex leaves
- 'Flamingo' - pink and white variegation (very popular)
- 'Pendulum' - with weeping branches.
- 'Variegatum' - creamy white leaf margins
- 'Violaceum' - younger shoots and branches have bluish colour
Although its light, close-grained, soft wood is considered undesirable for most uses, this tree has been considered as a commercial source of wood fiber, for use in fiberboard.
There is some commercial use of the tree for various decorative applications, such as turned items (bowls, stem-ware, pens). Primarily burl wood and injured wood, where the primary reason is this wood's reaction to injury, where the injured wood develops a red stain.
Use by Native Americans
The Navajo use the wood to make tubes for bellows. The Cheyenne burn the wood as incense for making spiritual medicines, and during Sun Dance ceremonies. They also mix the boiled sap with shavings from the inner sides of animal hides and eat them as candy.
The Meskwaki use a decoction of the inner bark as an emetic and the Ojibwa use an infusion of the inner bark for the same purpose. The Chiricahua and Mescalero Apache dry scrapings of the inner bark and keep it as winter food, and they also boil the inner bark until sugar crystallizes out of it. The Dakota also use the sap to make sugar, as do the Omaha, the Pawnee, the Ponca, the Winnebago and the indigenous people of Montana, who also freeze the sap and use it as a syrup The Ojibwa mix the sap with that of the sugar maple and drink it as a beverage.
The Cheyenne also use the wood to make bowls and to cook meat. The Keres make the twigs into prayer sticks. The native peoples of Montana also use large trunk burls or knots to make bowls, dishes, drums, and pipe stems.
Acer negundo was identified in 1959 as the material used in the oldest extant flutes from the Americas that were made of wood. These early artifacts, excavated by Earl H. Morris in 1931 in the Prayer Rock district of present-day Northeastern Arizona, have been dated to 620-670 CE.
The style of these flutes, now known as Anasazi flutes, uses an open tube and a splitting edge at one end. This design pre-dates the earliest extant Native American Flute (which use a two-chambered design) by approximately 1,200 years.
- "Acer negundo L.". NatureServe Explorer. Retrieved 2007-07-03.
- Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 [and more or less continuously updated since]. http://www.mobot.org/MOBOT/research/APweb/.
- The Plant List
- "BSBI List 2007" (xls). Botanical Society of Britain and Ireland. Retrieved 2014-10-17.
- Community trees of the Prairie provinces - Canadian Forest Service
- van Gelderen, C.J. & van Gelderen, D.M. (1999). Maples for Gardens: A Color Encyclopedia.
- Keeler, H. L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons. pp. 85–87.
- DePauw University
- Acer spp. Aceraceae Note that some of the common names given in this reference are questionable. "Stinking Ash" and "Black Ash" typically refer to Ptelea trifoliata and Fraxinus nigra, respectively. This reference is retained as an example of the confusion which arises when plants such as A. negundo are discussed by other than their scientific names.
- Elmore, Francis H. 1944 Ethnobotany of the Navajo. Sante Fe, NM. School of American Research (p. 62)
- Hart, Jeff 1992 Montana Native Plants and Early Peoples. Helena. Montana Historical Society Press (p. 4)
- Hart, Jeffrey A. 1981 The Ethnobotany of the Northern Cheyenne Indians of Montana. Journal of Ethnopharmacology 4:1-55 (p. 13)
- Smith, Huron H. 1928 Ethnobotany of the Meskwaki Indians. Bulletin of the Public Museum of the City of Milwaukee 4:175-326 (p. 200)
- Smith, Huron H. 1932 Ethnobotany of the Ojibwe Indians. Bulletin of the Public Museum of Milwaukee 4:327-525 (p. 353)
- Castetter, Edward F. and M. E. Opler 1936 Ethnobiological Studies in the American Southwest III. The Ethnobiology of the Chiricahua and Mescalero Apache. University of New Mexico Bulletin 4(5):1-63 (p. 44)
- Gilmore, Melvin R. 1913 Some Native Nebraska Plants With Their Uses by the Dakota. Collections of the Nebraska State Historical Society 17:358-70 (p. 366)
- Gilmore, Melvin R. 1913 A Study in the Ethnobotany of the Omaha Indians. Nebraska State Historical Society Collections 17:314-57. (p. 329)
- Gilmore, Melvin R. 1919 Uses of Plants by the Indians of the Missouri River Region. SI-BAE Annual Report #33 (p. 101)
- Smith, Huron H. 1932 Ethnobotany of the Ojibwe Indians. Bulletin of the Public Museum of Milwaukee 4:327-525 (p. 394)
- Hart, Jeffrey A. 1981 The Ethnobotany of the Northern Cheyenne Indians of Montana. Journal of Ethnopharmacology 4:1-55 (p. 46)
- Swank, George R. 1932 The Ethnobotany of the Acoma and Laguna Indians. University of New Mexico, M.A. Thesis (p. 24)
- Gilmore, Melvin R. 1913 A Study in the Ethnobotany of the Omaha Indians. Nebraska State Historical Society Collections 17:314-57. (p. 336)
- Vestal, Paul A. and Richard Evans Schultes 1939 The Economic Botany of the Kiowa Indians. Cambridge MA. Botanical Museum of Harvard University (p. 40)
- Blankinship, J. W. 1905 Native Economic Plants of Montana. Bozeman. Montana Agricultural College Experimental Station, Bulletin 56 (p. 16)
- Johnston, Alex 1987 Plants and the Blackfoot. Lethbridge, Alberta. Lethbridge Historical Society (p. 44)
- Robbins, W.W., J.P. Harrington and B. Freire-Marreco 1916 Ethnobotany of the Tewa Indians. SI-BAE Bulletin #55 (p. 38)
- Clint Goss (2011). "Anasazi Flutes from the Broken Flute Cave". Retrieved 2011-10-18.
Names and Taxonomy
fresno de Guajuco (Spanish)
Numerous varieties of this widely distributed species have been
Acer negundo var. negundo L.
Acer negundo var. interior (Britt.)Sarg.
Acer negundo var. violaceum (Kirchn.) Jaeg.
Acer negundo var. texanum Pax.
Acer negundo var. californicum Sarg.
Acer negundo var. arizonicum Sarg.
These varieties appear to represent fairly distinct geographic races.
Intergradation occurs between varieties and has been considerable
between var. violaceum and var. negundo .
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