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Exotic Burning Bush Invasive Species Profile

Exotic burning bush (Euonymus alatus) is native to northeast Asia and central China. It was introduced in the United States in the 1860s and it still widely planted today as an ornamental due to its brightly colored fall foliage. Unfortunately, it has spread from landscaping plantings and has become invasive in native habitats. The native burning bush (Euonymus atropurpureus), commonly known as eastern wahoo, is unfortunately lesser known and nurseries and greenhouses often only carry the exotic varieties.  Exotic burning bush is a very large dense shrub that can grow in nearly any habitat except those with poorly drained soils. It shades or crowds out native vegetation due to its large, dense growth.

burning bushes in landscaping planting
Exotic Burning Bush - Photo by Leslie J Mehrhoff, University of Connecticut, Bugwood.org

Habitat: Will grow in nearly any area from forest to prairie; doesn’t grow in wet areas. Most common invasions are in wooded areas.

Hardiness: Zone 4

Mature Shape: Large shrub

Height: Up to 20 feet tall

Site Requirements: prefers dry or moist soils; doesn’t grow in poorly drained areas

Leaves: simple, opposite, elliptical, finely toothed, 1-3 inches long, half inch to inch and a quarter inch wide, short petioles, bright pink or red in the fall

Flowering Dates: May to early June

burning bush twig with extensions that look like paddles or wings
Burning bush twigs with "wings" - Photo by Bary Rice, Sarracenia.com, Bugwood.org

Exotic burning bush is also sometimes called winged wahoo burning bush due to the “wings” that grow on the sides of the twigs. Twigs are green when young, and eventually turn brown. Bark on older plants is smooth; gray on the outside and pale on the inside.

Flowers are one third of an inch across and greenish yellow with 4 petals. They grow in clusters of 3. Fruits are red capsules that open to reveal red seeds.

The native burning bush, eastern wahoo, lacks winged stems and has purple-red flowers instead of greenish yellow flowers.

Control Methods

Avoiding the use of exotic burning bush in landscaping can help prevent their spread into nearby natural areas.  Once this plant escapes cultivation, control can be difficult, especially after it has become large and established. Cutting the plant and treating with herbicide is likely the most effective method. Read more about control of burning bush and other invasive species in our Chemical Control of Unwanted Vegetation article.

burning bush plant with green foliage
Burning bush plant - Photo by John Ruter, University of Georgia, Bugwood.org

burning bush green foliage
Burning bush leaves - Photo by Adam Janke, Iowa State University

  

burning bush infestation in the woods
Burning bush infestation - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

burning bush bark on mature plant
Burning bush bark - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

burning bush infestation in the fall
Burning bush infestation in the fall - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Buckthorn Invasive Species Profile

buckthorn invasive species thumbnail with photo of plant and link to youtube videoCommon buckthorn or European buckthorn (Rhamnus cathartica) and glossy buckthorn (Rhamnus frangula or Frangula alnus) originated in Eurasia and were brought to the Midwest to be used as hedges and for landscaping. Both species have a long growing season and a dense growth pattern that allows them to out-compete native vegetation. In the fall the yellow leaves on buckthorn plants are easily seen in the understory after most other plants have dropped their foliage. Buckthorn produces many dark berries that either drop to the ground and germinate or are eaten by birds and small mammals and spread across the landscape. Common buckthorn grows in open woodlands and on woodland edges, although it can also be found in prairies, yards, and along roads. Glossy buckthorn can grow in full sun and in heavily shaded areas. Although both species can be found in drier areas, common buckthorn prefers well-drained soils and glossy buckthorn thrives in wet soils. The ability of buckthorns to grow so quickly and in such a wide variety of habitats and soil types makes them particularly concerning exotic invasive species. Additionally, buckthorn is the host plant for soybean aphids, which makes it even more problematic in Iowa. Common buckthorn is listed in Iowa as a primary noxious weed.

common buckthorn leaves
Common Buckthorn Leaves - Photo by Chris Evans, University of Illinois, Bugwood.org

Habitat: Both common and glossy buckthorn can be found in a wide variety of habitats from prairies to woodlands though their impacts are greatest in wooded areas.

Hardiness: Zone 3

Mature Shape: Small tree or tall dense shrub

Height: 25 feet

Width: Trunk up to 10 inches in diameter

Site Requirements: Common buckthorn prefers well-drained soils; glossy buckthorn can be found in drier areas but does best in wet soils.

Leaves: Common buckthorn leaves are 1-1.5 inches long, simple, opposite or sub-opposite (occasionally alternate), hairless, round or oval with a pointed tip, and have finely toothed margins. Common buckthorn has 3-4 pairs of veins. Glossy buckthorn leaves are 1-3 inches long, simple, usually alternate, and oblong with smooth margins. Glossy buckthorn leaves have 6-9 pairs of veins.      

Flowering Dates: Common: May-June; Glossy: May to first frost

Buckthorn flowers emerge from the leaf axils and are small with white or greenish yellow petals. Common buckthorn flowers have 4 petals and glossy buckthorn flowers have 5 petals. Buckthorn fruit are pea-sized, berry-like, drupes that start out as red and turn black as they ripen in the late summer to early fall. Glossy buckthorn can have branches with fruit in varying stages of ripeness throughout the summer and fall.

Common buckthorn has gray-brown bark that becomes flaky and darker gray-black as the plant ages. Common buckthorn often resembles the bark of plum and cherry trees. Both species have prominent lenticles, yellow sapwood, and pinkish orange heartwood. Common buckthorn has thorns but glossy buckthorn does not.

Control Methods

Removing buckthorn plants early, before they produce fruits is the most effective way to prevent them from spreading. If the plants are still within their first year of growth but there are too many seedlings to remove by hand, prescribed fire in the fall or early spring can be effective. A prescribed fire may need to be performed for two to three years in a row depending if there are seeds in the soil that will sprout the year following the initial burn. Caution should be taken to make sure native plants can tolerate repeated burning. Combining fire with grazing goats can also be effective. Once buckthorn has formed dense thickets, fire is generally not an effective control method. If manual control is not practical, see our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods.

yellow inner bark
Buckthorn Inner Bark - Photo by Billy Beck, Iowa State University

pinkish orange heartwood
Buckthorn Inner Bark - Photo by Billy Beck, Iowa State University

young speckled common buckthorn bark
Young Common Buckthorn Bark - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

common buckthorn rough bark
Common Buckthorn Bark - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

common buckthorn fruit - black berries
Common Buckthorn Fruit - Photo by Chris Evans, University of Illinois, Bugwood.org

glossy buckthorn bark
Glossy Buckthorn Bark - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

common buckthorn flowers on plant
Common Buckthorn Flowers - Photo by Rob Routledge, Sault College, Bugwood.org

common buckthorn twig
Common Buckthorn Twig - Photo by Paul Wray, Iowa State University, Bugwood.org

white glossy buckthorn flowers
Glossy Buckthorn Flowers - Photo by Rob Routledge, Sault College, Bugwood.org

Garlic Mustard Invasive Species Profile

garlic mustard thumbnail with image of plant and link to youtube videoGarlic mustard (Alliaria petiolata) is an herbaceous, biennial forb that was introduced from Europe in the mid-1800s. This highly invasive exotic species grows and spreads extremely quickly, forming thick stands that shade-out and out-compete native understory plants and tree seedlings, to the point of completely suppressing their growth. Additionally, garlic mustard can release allelochemicals into the soil that prevent seeds of other species from germinating. Few animals or insects eat this plant in the U.S., so without human intervention it can spread. One garlic mustard plant can produce hundreds of seeds that remain viable in the soil for 5 or more years. These seeds are easily spread on the fur and feet of animals and through human activity.

Garlic mustard has two different growing phases. In the first year, seedlings have round or heart shaped leaves with scalloped edges that often resemble creeping charlie. In the second year, the plant produces a stalk with triangular leaves that are sharply toothed. Flowers grow at the top of the stalks or in the leaf axils and long, thin, green pods with shiny black seeds form soon after.

garlic mustard plant in bloom
Second Year Garlic Mustard Plant in Bloom - Photo by Chris Evans, University of Illinois, Bugwood.org

Habitat: Forests, along trails, yards, roadsides; prefers shaded areas but can also be found in full sun

Height: First year: 1-6 inches, second year with stalk 1-4 feet

Site Requirements: Cannot tolerate acidic soil

Leaves: Smell like garlic when crushed. First year: round or heart-shaped rosette 1-6 inches across with scalloped edges, not clasped around the flower stalk; second year: sharply toothed triangular leaves 2-3 inches across, alternately attached to flowering stalk

Flowers: small white with four petals that are 0.25 inches wide  

Flowering Dates: April-June

Seed Dispersal Dates: July-August

Seed Bearing Age: Produce seeds in the second year of growth (plants die after seed production)

Garlic mustard plants usually have one or two stems but plants that have been cut will sometimes have more. Plants also have a white taproot.

Control Methods

The Iowa DNR has a guide to controlling garlic mustard throughout the year. Prescribed fire can be used in early spring and can be followed up with torching if seedlings continue to emerge. Hand pulling can be extremely effective from April through June, before seeds start falling. It is important to stay out of garlic mustard infested areas from July through October to prevent spreading seeds. Check out our Chemical Control of Unwanted Vegetation article for herbicides and application methods.

garlic mustard infestation in a forest
Garlic Mustard Infestation - Photo by Steven Katovich, Bugwood.org

green stem of garlic mustard seed pods
Garlic Mustard Seed Pods - Photo by Chris Evans, University of Illinois, Bugwood.org

white flowers on garlic mustard plant
Garlic Mustard Flowers - Photo by Chris Evans, University of Illinois, Bugwood.org

first year garlic mustard rosette
Garlic Mustard First Year Rosette - Photo by Chris Evans, University of Illinois, Bugwood.org

Multiflora Rose Invasive Species Profile

multiflora rose thumbnail with photo of plant and link to youtube videoMultiflora rose (Rosa multiflora) is native to Japan, the Koreas, and eastern China. It was brought to the U.S. in the mid to late 1800s as an ornamental plant that was valued for its showy clusters of fragrant white to pink flowers. Unfortunately the invasive potential of this plant was not realized until after it was widely used for soil erosion control, living snow fences, highway median barriers, and livestock fences in the early 1900s. Multiflora rose grows very quickly and often forms extremely dense thickets that eliminate nearby plants, reducing understory diversity and limiting growth of livestock forage in pastures.  When the arching stems or canes of a multiflora rose plant reach the ground they are able to root and further spread the plant. Additionally, each plant is capable of producing hundreds of thousands of seeds per year that stay viable in the soil for 10-20 years. The fruits and seeds attract birds and small mammals which disperse the plant into new areas. Multiflora rose is classified as a noxious weed in Iowa and multiple other states in the Midwest.

multiflora rose in bloom with white flowers
Multiflora Rose Plant - Photo by James H. Miller, USDA Forest Service, Bugwood.org

Habitat: Grows in a wide variety of soil, moisture, and light conditions; can be present in wooded areas, pastures, prairies, and along roadsides and stream banks.

Hardiness: Zone 5

Mature Shape: Shrubby with long arching stems

Height: 10 - 15 feet

Width: 9 – 13 feet

Site Requirements: Grows in nearly all soil types but not in standing water.

Leaves: average 2.5 inches long and 0.75 inches wide (can range from 0.5 – 4 inches long), alternate, pinnately compound with 5-11 oval leaflets which have toothed margins, petioles have fringed stipules with glands that look like small red, brown, or black specks.   

Flowering Dates: May-June

multiflora rose plant showing fringed stems
Multiflora Rose Plant with Fringed Stipules - Photo by Chris Evans, University of Illinois, Bigwood.org

Multiflora rose flowers are white or pinkish and have 5 petals. Green fruit form in August and turn red and then remain on the plant through winter. Younger stems are green or red and turn gray-brown with age. Larger, older stems turn gray-brown and often have vertical cracks. Stems are round with large curved thorns and generally don’t get larger than one inch in diameter.

Iowa’s native wild prairie rose (Rosa prantincola) does not form dense thickets like the exotic invasive multiflora rose and only grows about 2 feet tall. It also does not have fringed stipules. 

Control Methods

The thorns on multiflora rose plants make mechanical control challenging. It is important to remove all of the roots when digging up multiflora rose because new plants will develop from leftover sections of root. Mowing or cutting can be effective if it is done three to six times during the growing season. This must be done for two to four years to be most effective. Combining prescribed fire with other control methods can also be effective. See our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods. Chemical control treatments must also be repeated because the large number of long-lived seeds in the soil will sprout even after the original plant has been eradicated.

red multiflora stem with thorns and leaves
Multiflora Rose Stem - Photo by Chris Evans, University of Illinois, Bugwood.org

pink multiflora rose flowers
Multiflora Rose Flowers - Photo by  Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

brown multiflora rose twig with thorns
Older Multiflora Rose Stem - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

multiflora rose leaves
Multiflora Rose Leaves - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

multiflora rose infestation on woodland edge
Multiflora Rose Infestation - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

multiflora rose stem with red berries
Multiflora Rose Fruit - Photo by Barry Rice, sarracenia.com, Bugwood.org

Honeysuckle Invasive Species Profile

honeysuckle thumbnail with photo of plant and link to youtube videoMultiple honeysuckle (Lonicera) species can be found in Iowa. The exotic species, including primarily bush honeysuckle (Lonicera maackii) or Tartarian honeysuckle (Lonicera tatarica), originally came from Eurasia. Exotic honeysuckles were used as ornamental shrubs and, before it was clear that these plants would take over so easily, they were planted for wildlife habitat or ground cover meant to prevent erosion. Now we know these plants grow so quickly they out-compete native understory plants, which actually reduces the quality of forest habitat. In contrast, native wild honeysuckle (L. dioica var glaucescens) and grape honeysuckle (L. reticulata), are not invasive and do not form dense thickets like the exotic species.

Habitat: Commonly found in sunny areas such as open woodlands and woodland edges but also in pastures, on the side of the road, and in abandoned fields. Highly disturbed areas such as grazed woodlands are also commonly invaded by non-native honeysuckles. Various species are suited to both upland and lowland habitat types.

thick honeysuckle growth along gravel road in the woods
Honeysuckle Infestation - Photo by Chris Evans, University of Illinois, Bugwood.org

Hardiness: Zones 3-6

Mature Shape: The exotic L. maackii and L. tatarica are bushes 

Height: 6-18 feet

Site Requirements: most species prefer sun but will tolerate shade, except L. maackii which will grow in full shade

Leaves: simple, opposite, oval, untoothed margins, short petioles; occasionally two leaves will fuse together under the clusters of flowers or fruits

Flowering Dates: May-June

Seed Dispersal Dates: Late summer to early fall

The irregular tubular flowers are pink, white (turn yellow with age), or reddish purple. Exotic honeysuckles have fragrant flowers while native honeysuckles generally do not. The fruit are red or orange berries which are present June-July and October-November. Honeysuckle bark is shaggy and gray or tan in color. Twigs of all species can be hollow. However, the twigs of native species tend to be less hollow with a white pith whereas the exotic species are more obviously hollow with a brown pith.

pink flowers on a honeysuckle plant
Honeysuckle Flowers - Photo by Leslie J. Merhoff, University of Connecticut, Bugwood.org

Exotic honeysuckle leaves emerge one to two weeks before the leaves of native trees and shrubs and don’t drop until later in the fall. This can be useful for identifying honeysuckle invasions in a forest. With their early leaf emergence, exotic honeysuckles are able to shade out native plants and then dominate an area by using up the moisture and nutrients in the soil. Exotic honeysuckles may even release allelochemicals into the soil that prevent other plants from emerging around them.

Control Methods

All chemical or mechanical control of honeysuckle should be conducted before late summer when seeds are dispersed to reduce the likelihood that treated areas will be reinvaded. In the spring, small and medium sized plants can be pulled or dug up. It is important to ensure that plants that have been dug up do not reroot if they are simply laid on the ground. For larger plants it is almost always necessary to use chemical control methods after cutting. See our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods. If an infestation is very small it can be effective to cut the plants several times a year for two years without needing to use chemical control. Prescribed fire can be moderately effective for controlling non-native honeysuckle when used in the spring. Combing prescribed fire with grazing goats can also be effective.

honeysuckle trunk showing bark
Honeysuckle Bark - Photo by Adam Janke, Iowa State University

green honeysuckle bushes in the winter with snow on the ground
Winter Honeysuckle Infestation - Photo by Adam Janke, Iowa State University

honeysuckle plants in the forest
Honeysuckle Infestation - Photo by Adam Janke, Iowa State University

white flowers on honeysuckle plant
Honeysuckle Flowers - Photo by Leslie J. Merhoff, University of Connecticut, Bugwood.org

honeysuckle leaves and berries
Honeysuckle Fruit - Photo by Chris Evans, University of Illinois, Bugwood.org

honeysuckle leaves
Honeysuckle Leaves - Photo by Adam Janke, Iowa State University

honeysuckle twig with hollow center
Honeysuckle Twig with Hollow Pith - Photo by Adam Janke, Iowa State University

Oriental Bittersweet Invasive Species Profile

oriental bittersweet thumbnail with photo of plant and link to youtube videoOriental bittersweet (Celastrus orbiculatus), also known as Asiatic or round-leaved bittersweet, is a shade tolerant woody vine native to eastern China, Korea, and Japan. It grows quickly and will invade forests, open woodlands, grasslands, roadsides, and fencerows. Birds eat its berries and spread the seeds, which further disperses the plant into new areas. Oriental bittersweet will completely cover and shade out native plants. It is even capable of wrapping so tightly around trees that it kills them. As stands of Oriental bittersweet grow denser and invade the canopy level, their weight alone can cause trees to blow over in high winds.

Habitat: Commonly found along forest edges, in open woodlands, and in early successional areas but is shade tolerant and can spread from the edges into forested areas as well.

oriental bittersweet red and orange fruit
Oriental Bittersweet Fruit - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Hardiness: Zone 4

Mature Shape: Vine that can be up to 60 feet long and 5 inches in diameter; may become shrub-like as it spreads

Leaves: Simple, alternate, 2-5 inches long, finely toothed, glossy, rounded with long tip; leaves turn yellow in the fall and stay on the vine late into the season

Flowers: small, greenish-yellow with 5 petals; grow in clusters at the leaf axils

Fruits: Initially greenish-yellow berries in the summer, turning to red, yellow, and orange in the fall. Fruits grow along the stem of the plant, distinguishing it from native bittersweet.

Flowering Dates: May-early June

American bittersweet (Celastrus scandens) is a native form of bittersweet that grows in the same habitat as Oriental bittersweet. American bittersweet flowers and fruits appear at the tips of the branches rather than along the stems at the leaf axils as in Oriental bittersweet. For more information on differentiating between American and Oriental bittersweet download the USGS American and Oriental Bittersweet Identification guide. Oriental bittersweet poses a threat to native bittersweet as it out-competes and hybridizes with it.

Control Methods

Small patches of Oriental bittersweet can be removed by pulling plants out by the roots and removing them from the area. This should be done before fruiting to prevent distribution of seeds. If fruiting has already occurred it is necessary to put any pulled vines in a bag and leave the bags in the sun to kill the seeds. See our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods.

oriental bittersweet leaves
Oriental Bittersweet Leaves - Photo by Chris Evans, University of Illinois, Bugwood.org

oriental bittersweet vines covering trees
Oriental Bittersweet Infestation - Photo by Nancy Loewenstein, Auburn University, Bugwood.org

leafless oriental bitter sweet vine wrapping around tree trunk
Oriental Bittersweet Vine - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

oriental bittersweet whiteish green flowers
Oriental Bittersweet Flowers - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Japanese Barberry Invasive Species Profile

Japanese barberry (Berberis thunbergii) is a small to medium, dense shrub that was originally planted as hedges in landscaping but has spread to native habitats. Japanese barberry is capable of changing soil characteristics in order to help itself outcompete native plants and also has early spring leaf emergence that allows it to shade out any nearby competitors. The native Midwestern barberry Berberis Canadensis and the introduced Berberis vulgaris were successfully eliminated through a federal eradication program because they are able to host black stem rust, which kills small grain crops. Japanese barberry is not a host for this agricultural pest so efforts to eliminate it due to its invasive nature have been less systematic and efficient.

Japanese barberry shrub in the fall with red foliage
Japanese Barberry Plant - Photo by Adam Janke, Iowa State University

Habitat: Woodlands, trails, roadsides, fencerows, pastures, bottomlands, and highly disturbed areas

Hardiness: Zone 4

Mature Shape: Shrub

Height: 2-8 feet

Site Requirements: Shade tolerant; grows in various soil types but does best in well-drained soil

Leaves: simple, alternate, oval, untoothed with elongated petioles, 0.5 to 1.5 inches long; grow in clusters; turn yellow, orange, red, or purplish in the fall

Flowering Period: May

Japanese barberry twigs are ridged with spines. Newer twigs and stems turn reddish in the winter and become gray as they age. Inner bark is yellow on the branches and roots.

Flowers are one-third of an inch wide and are yellow. They can be single or can grow in small clusters of 2-4 with stems coming from a single point. Japanese barberry produces small, bright red, egg-shaped berries which remain on the plant even after the leaves have fallen.

Control Methods

Use of Japanese barberry and other invasive species in landscaping contributes to their spread into natural areas. Avoiding the use of these species is the first step to helping control their invasion.

In addition to spreading through seed dispersal, Japanese barberry is able to form rhizomes (underground horizontal stems) and spread via roots so it is necessary to remove all connecting roots when digging the plant up. Once large plants are removed, regular mowing where possible can be effective. Spring prescribed fire can also be used for control. Even after plants have been removed treatment may have to be continued for a few years as seeds sprout. See our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods.

Japanese barberry infestation
Japanese Barberry Infestation - Photo by Andy Bartlett, Iowa DNR

Japanese barberry infestation
Japanese Barberry Infestation - Photo by Brian Button, Iowa DNR

clusters of yellow japanese barberry flowers
Japanese Barberry Flowers - Photo by Richard Gardner, Bugwood.org

Japanese barberry twigs with thorns
Japanese Barberry Twigs - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

two Japanese barberry bushes, one with neon green leaves and one with purple leaves
Japanese Barberry Bushes - Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Japanese barberry red berries
Japanese Barberry Fruit - Photo by Adam Janke, Iowa

Reed Canary Grass Invasive Species Profile

reed canary grass thumbnail with photo of plants and link to youtube videoReed canary grass (Phalaris arundinacea) is native to Europe, Asia, and North America. The European variety is particularly aggressive and it is likely that the invasive varieties are cultivars that were crossbred for fast growth. Reed canary grass is a cool-season perennial that typically invades wetlands and floodplains but it can also grow in dry soils in shaded wooded areas. It is a sod-forming grass that spreads through rhizomes (underground horizontal stems) and runners. Once it has invaded an area it can completely eliminate other vegetation because of its dense growth. It can even inhibit tree growth in floodplain forests.

Habitat: typically areas with wet soils including primarily wetlands and floodplains adjacent to rivers and streams

Height: 2-9 feet

reed canary grass beside a trail
Reed Canary Grass - Photo by Rob Routledge, Sault College, Bugwood.org

Site Requirements

Leaves: flat, gradually tapering, hairless blade is rough on both sides, 1-4 feet long and up to 0.75 inches wide; long membranous ligule  

Flowering Dates: May-July

The branching flower clusters (panicles) of reed canary grass are 3-6 inches long. Flowers are initially greenish purple and change to yellowish brown as seeds mature.

Control Methods 

Reed canary grass is difficult to control so a combination of methods is necessary. Control practices need to suppress above ground growth, address below ground rhizomes and seed bank, and promote native species to compete with reed canary grass. The timing of treatment is important and persistence is key. Generally control methods will need to be applied for at least 3-5 years in a row. Reed canary grass rebounds quickly if a single year is skipped. In Iowa, cattle grazing, disking, mowing, and chemical control have been effective to varying degrees. Our chemical control of unwanted vegetation article has information on specific herbicides to use. For more detailed information on timing and methods of control check out this reed canary grass management guide.  

reed canary grass branching flower clusters showing young green flowers to purple flowers and yellowish brown mature clusters with seeds

 stages of reed canary grass flower clusters - Photo by Leslie J Mehrhoff, University of Connecticut, Bugwood.org

reed canary grass blades
Reed Canary Grass Blades - Photo by Ohio State Weed Lab, The Ohio State University, Bugwood.org

 

reed canary grass infestation
Winter Reed Canary Grass Infestation - Photo by Adam Janke, Iowa State University

reed canary grass infestation
Reed Canary Grass Infestation - Photo by Leslie J Mehrhoff, University of Connecticut, Bugwood.org

Tree of Heaven Invasive Species Profile

The tree of heaven (Ailanthus altissima), also known as Chinese sumac, copal-tree, stink tree, and varnish tree, is a problematic exotic invasive species in Iowa. It is often confused with sumac; however, the tree of heaven can be distinguished by the foul odor it emits.

Tree of heaven produces many seeds, grows extremely quickly, and can out-compete native plants. It can rapidly take over a site and form dense thickets. Tree of heaven is also known to produce allelochemicals that prevent other plants from growing around it.

tree of heaven
Tree of Heaven - Photo by Chuck Bargeron, University of Georgia, Bugwood.org

Habitat: Disturbed areas, especially floodplain areas and wooded drainages that are commonly disturbed by flooding, fields, fence rows, roadsides, woodland edges, and forest openings. 

Hardiness: Zones 4 through 8

Growth Rate: Fast

Mature Shape: Rounded

Height: 70-100 Feet

Width: 35-50 feet

Site Requirements: Full sun on well drained moist soil, but can survive almost anywhere

Flowering Dates: April - July

Seed Dispersal Dates: Fall - Winter

Seed Bearing Age: 2-3 years

Seed Bearing Frequency: Yearly

Seed Stratification: Prechill for 2 months at 34°F to 40°F

It is a deciduous tree that can grow 40 to 60 feet tall, maximum height of 89 feet, with a trunk diameter of 2 to 3 feet. The leaves are alternate, pinnately compound, 1 to 3 feet long, with thick smooth petioles; having 11 to 41 leaflets, each 1 to 2 inches long, ovate-lance shaped, unequal base, entire margins with teeth at the base and dark green on top and paler underneath. The fruit or seeds are winged papery samaras; red, yellow, and green, and hang in dense clusters.

In June the pistillate trees bear large clusters of seeds, and the staminate trees emit a malodorous stench.  The tree of heaven grows rapidly and is very difficult to eradicate once its established – competes aggressively with more desirable native trees. 

A native to China and Taiwan and naturalized in North America – commonly cultivated. Considered an invasive species along roadsides, and neglected property, especially in and around urban areas.

Control Methods

The effectiveness of mechanical control on tree of heaven is limited. An important growth feature that makes control challenging is the tendency of tree of heaven plants to produce many sucker plants after being cut, which often makes the infestation worse. Therefore, cutting and prescribed fire are not recommended for controlling tree of heaven. In small areas, young seedlings can be pulled or dug up, especially when soil is moist to allow for easier removal. All roots and root fragments must be removed to prevent new plants growing from any pieces left behind. Chemical control is the most effective treatment. However, tree of heaven is very tough to control, and second-year or follow up monitoring is critical. Even with chemical control, monitoring the site should continue to make sure seedlings and potential suckers and root sprouts are treated. Go to our chemical control of unwanted vegetation article for information on specific herbicides to use. Check out our invasive species page to learn more about invasive species in Iowa.

bright orange, yellow, and green tree of heaven fruit
Tree of Heaven Fruit - Photo by Chuck Bargeron, University of Georgia, Bugwood.org

tree of heaven leaves
Tree of Heaven Leaves - Photo by Paul Wray, Iowa State University

tree of heaven trunk showing dark bark with light diamond shaped spots
Tree of Heaven Bark - Photo by Paul Wray, Iowa State University

tree of heaven twig with cross section showing inner bark
Tree of Heaven Twig - Photo by Paul Wray, Iowa State University