Kudzu (Pueraria montana)

Introduction & Distribution  |  Biology & Identification  |  Habitat & Ecology  |  Impacts  |  Control  |  Policy  |  New York Distribution Map

 

Introduction & Distribution

Kudzu (Pueraria montana) is a semi-woody, trailing or climbing, perennial invasive vine native to China, Japan, and the Indian subcontinent. Kudzu is also known as foot-a-night vine, Japanese arrowroot, Ko-hemp, and “the vine that ate the South.” The vine, a legume, is a member of the bean family. It was first introduced to North America in 1876 in the Japanese pavilion at the Philadelphia Centennial Exposition. A second major promotion of kudzu came in 1884 in the Japanese pavilion at the New Orleans Exposition. The first recorded use of kudzu in North America was as a shade plant on porches in the American South (the plant produces attractive, fragrant purplish flowers in mid-summer). Kudzu was heavily promoted in the early-1900s when the government paid farmers to use the vine for erosion control (more than a million acres are estimated to have been planted as a result) and as a drought-tolerant, nitrogen-fixing legume (capable of bacterial growth with stem and root nodules converting free nitrogen to nitrates, which the host plant utilizes for its growth in low nitrogen soils) for livestock feed. During the Great Depression, thousands of acres of kudzu were planted by the Civilian Conservation Corps for hillside stabilization projects. In some areas, kudzu blossoms have been prized for their use in making kudzu blossom jelly and jam. The long kudzu fibers are also used in basket making. Ko-hemp, a more refined version of kudzu fiber has long been used for cloth weaving in China.

 

These government-sanctioned uses of the vine, combined with its innate, aggressive, range-expansion capabilities resulted in a rapid spread of kudzu throughout North America. Kudzu can now be found in 30 states from Oregon and Washington State to Massachusetts, particularly infesting states from Nebraska and Texas eastward most heavily; the vine is most common in the South. It has also been discovered in Hawaii and the warm, south-facing growing region on the north shore of Lake Erie in the Canadian Province of Ontario.

 

Biology & Identification

Kudzu is an herbaceous to semi-woody, climbing or trailing, nonnative, deciduous, perennial vine or liana (a vine that is rooted in ground-level soil and uses trees and other vertical supports (telephone polls, buildings, etc.) to climb to the forest canopy to get access to light. A well-known example would be common wild grape).

 

Kudzu produces long, hairy vines from a central root crown. Kudzu has dark-green, hairy, alternate, compound leaves, 2 – 8 inches (5 – 20 cm) in length with three oval- to heart-shaped leaflets 3 – 4 inches (8 – 10 cm) long at the end; these leaves may be slightly or entirely lobed. Stems are also hairy. Vines can grow up to 30 to 100 feet (9 – 30.5 meters) per year. The vines have 0.8 – 1 inch (2 – 2.5 cm) flowers on 4 – 8-inch (10 – 20 cm) axillary racemes (short, equal length stalks along a main stem forming clusters of flowers with the oldest flowers toward the base with the newest end of the stalk terminating in one or more undeveloped buds). Vertical kudzu vines in full sunlight produce flowers in late-summer; horizontal vines seldom produce flowers. The flowers are typically red, purple, or magenta with a strong, grape-like aroma; pink or white flowers occur occasionally.

 

 

Population Expansion

Kudzu populations spread both asexually and by seed germination.

Asexual (vegetative) spread:

The most common method of spread is by setting new root crowns at almost every node where horizontal trailing stems come in contact with bare soil (this can be every few feet); new vines will form at these nodes the following spring and will spread out in all available directions. Kudzu tap roots can grow up to 12 feet (3.6 meters) long and weigh up to several hundred pounds. This may help kudzu to withstand long periods of drought.

 

Sexual spread:

Kudzu usually does not flower until its third year, with flowers and seeds forming only on vertical climbing vines. Kudzu produces clusters of 20 – 30 hairy brown seed pods, 1.6 – 2 inch (4 – 5 cm) long pods. Each pod contains from 3 to 10 kidney bean-shaped seeds, of which only 1 or 2 seeds are viable. Dormant  viable seeds are unable to germinate until after their seed coats have become water permeable as a result of physical scarification (breaking the seed coat by abrasion or prolonged thermal stress). Seeds deposited below the vines in the seed bank may take several years to germinate. This can be problematic during control efforts because it can result in the reemergence of the plants years after eradication was believed to have been achieved. It has been observed that kudzu in North America is more likely to grow asexually than by setting seed. It appears that this is due to kudzu seedlings being outcompeted by vegetatively produced vines.

 

 

Habitat & Ecology

Factors that help determine how invasive kudzu will be in any habitat appear to be climate and availability of light. Warmth and humidity are important factors, with greater colonization corresponding to warmer average annual temperatures and higher average humidity. To reach additional light, the vines climb existing vegetation and hard vertical surfaces. It does not appear that the composition of the local native plant community has much influence on kudzu invasiveness. Even undisturbed plant communities adjacent to an existing population of kudzu can be at risk. Typical kudzu habitats are usually open, disturbed areas such as roadside ditches, rights-of-way, and abandoned fields. In such settings, kudzu can form large monocultures with thousands of plants per acre.

Kudzu has a strong daily leaf orientation capability; by controlling the leaf position as it faces toward or away from the sun, kudzu can control sunlight intensity on the leaflets that are exposed. This ability can reduce leaf temperatures relative to native vegetation and minimize the amount of water lost from the plant by leaf surface transpiration during times of peak sunlight. It may also be a benefit below forest canopies where light is dim by increasing the surface area of leaves receiving sunlight. Leaves exposed to open sunlight may be able to maximize photosynthesis, store additional food in kudzu’s rhizomes, and have a competitive advantage over native vegetation.

Kudzu accumulates and maintains substantial carbon reserves in large woody, tuberous roots, again giving it a competitive advantage.

Trailing stems in open areas tend to die back in the winter. Vertically climbing vines develop thick bark and can reach diameters greater than 0.8 inch (2 cm), aiding in overwintering.

Kudzu vines can more easily grow around smaller vines such as honeysuckle (Lonicera spp.) than around bare tree trunks. This growth tactic appears to aid the plant in the formation of lianas in forested areas. Once established, kudzu lianas compete with forest trees both for sunlight in the crown and for water and nutrients from the soil. The vines may directly damage colonized trees by strangulation. These physical traits of a kudzu liana significantly impact the ability of native trees to grow and reproduce, increasing the early mortality of native trees, and preventing the establishment of new trees or shrubs in the dim light below the colonized canopy.

Kudzu lianas can cause weakened trees to fall from the weight of the overgrowth of vines or by pulling down trees attached to the liana when one weak tree succumbs to the weight of ice freezing onto the tree and/or the vines.

Kudzu thrives where the climate favors mild winters (40 – 60°F {4 -16°C}), summer temperatures rising above 80°F (27°C), precipitation greater than 40 inches (101 cm), and a long growing season.

Because of its underground root crowns, kudzu can escape fire damage. During the growing season, kudzu’s underground root system can provide significant water to the foliage; the high water content stems and foliage are able to resist some fire damage that may kill nearby native plants.

There is some indication (not yet definitively proven) that wildfire (or controlled burn) soil heating may promote kudzu seed germination by scarifying the seedcoat which would allow penetration by water to allow for germination.

 

Impacts

Native Plant Community Impacts:

A kudzu invasion can cause several different types of major impacts on native plant communities: it can crowd them out; it can outcompete them; and it can physically crush them.

Since kudzu can fix nitrogen in its roots, it can thrive in soils too low in nitrogen to support robust growth of native vegetation, thereby outcompeting native plants for both nutrition and growing space, ultimately forming monospecific plant communities. This significantly alters natural plant communities and the animals that rely on those natural communities for food and habitat. Areas of more than 100 acres (40 hectares) with 1 – 2 plants per square foot, or 40,000 to 85,000 plants per acre (107,000 to 215,000 plants per hectare) can be found in the American South.

Kudzu’s rapid growth rate and its manner of growing over whatever it encounters in its path can also overwhelm native plant communities, also resulting in monospecific stands of the vine.

As heavy infestations of kudzu can completely cover trees of almost any size, kudzu lianas can both fell trees from their extreme weight or nearly eliminate light availability within the forest canopy, weakening or killing shade-intolerant species, particularly pines. Once kudzu gains access to the forest canopy, the liana formed can spread faster and more aggressively through a forest.

 

 

Economic Impacts:

By outcompeting, smothering, and physically removing native vegetation, kudzu damages to lost forest production for southern commercial timber producers has been estimated to be as high as $48 per acre ($118 per hectare) per year. Kudzu control costs can be as high as $200 per acre per year. Control costs on power company rights-of-way and transmission equipment have been estimated as high as $1.5 million per year. Kudzu can also be a problem along highway rights-of-way.

 

 

Control

With a growth rate of up to one foot (0.3 meter) per day, simply controlling or managing kudzu can become a “fool’s errand” of never ending activity. In areas where the plant cannot be tolerated at all, kudzu control is basically kudzu eradication. To prevent reinvasion, complete eradication is required, which means every root crown on a site must be killed. Due to the numerous root crowns at vine nodes, eradication of a well-established population of kudzu could take 5 – 10 years of concentrated effort. The more mature the population, the more difficult eradication becomes as a result the numerous crowns and the large rhizome system that can store significant amounts of starch to feed the plant. Lianas are also more efficient at producing starch and sending it to the root system than are horizontal, ground-based vines.

Eradication of kudzu with herbicides calls for frequent defoliation during the growing season, while most of the plant’s energy is devoted to vine production and growth. Defoliation forces the plant to call on root starch reserves to resume foliage growth activities, helping to diminish reserves of starch and prevent storage of new reserves. If a single treatment is all that can be undertaken in a year, it should be implemented in early-fall as foliage starch allocation to the root system replenishing that used for growth during the spring and summer takes place in the early-fall.

If physical or mechanical control methods are selected, eradication of well-established kudzu populations could take many years or be ineffective in the long-term. Mechanical harvesting of kudzu foliage limits the production of new food reserves by reducing photosynthesis; regrowth helps to deplete starch stored in the root system. Mowing of trailing vines and root crowns every two weeks may take up to ten years to eradicate small, immature patches of kudzu, assuming that all root heads are mowed. Mowing is more likely to result in eradication if used with herbicide application. During mechanical eradication efforts, all cut plant material should be destroyed by burning or by bagging and landfilling.

The use of intensive conservation grazing by herbivores such as sheep or goats can help control young, tender kudzu growth and make control by herbicides more effective over shorter periods of time by helping to reduce energy reserves.

For information regarding appropriate use of herbicides against kudzu and other invasive plants, please consult The Nature Conservancy’s Weed Control Methods Handbook. Make certain to consult your state’s environmental conservation or natural resource management agency to determine which herbicides are legal for kudzu control in your state.

 

 

Policy Status

In the 1950s, the Agricultural Conservation Program removed kudzu from the list of species acceptable for use as an agricultural forage crop or soil stabilization plant. Congress listed kudzu as a Federal Noxious Weed in 1998. In 2014, the State of New York designated kudzu as a prohibited plant under the state’s Environmental Conservation Law.

New York Distribution Map

This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.

Introduction and Distribution  |  Habitat, Biology, and Ecology  |  Impacts  |  Prevention  |  Control and  Management | New York Distribution Map

 

Introduction & Distribution

Wild parsnip (Pastinaca sativa) is a biennial/perennial herb native to Eurasia. In appearance, it looks and smells quite like cultivated parsnip (in point of fact, wild parsnip is part of the Apiaceae (or Umbelliferae) family which includes carrots, celery, parsley, parsnip, Angelica, and Queen Anne’s Lace, most of which are aromatic plants with hollow stems). It is believed to be an escapee from parsnip that was originally under cultivation. The plant typically can grow up to 4 feet (1.2 m) tall in an average year. Wild parsnip is common throughout the northern United States and southern Canada. Its range reaches from Vermont to California and south to Louisiana (it is not found in Hawaii, Mississippi, Alabama, Georgia, and Florida). Reported populations can be found across New York State with the heaviest concentrations being found in the Lower Hudson Valley, Catskills, and southern Adirondacks.

 

Habitat, Biology & Ecology

Wild parsnip is an herbaceous plant which can grow from 4 – 5 feet (123 – 150 cm) tall. It can survive in a broad range of environmental settings, from dry soils to wet meadows. It grows best in rich, calcareous, alkaline, moist soils. It is commonly found growing along roadsides, in pastures, and in abandoned fields, or any place where the soil has been disturbed and native vegetation has yet to become fully established.

The roots are generally smooth and cylindrical, although sometimes lateral roots will grow out from the central tap root.

Seedlings emerge from February through April, form rosettes in their first year, and grow vegetatively for one or more years, at which time they will form an aerial shoot (called a “bolt”) and flower. Wild parsnip produces a rosette of broad, hairless, ovate, compound pinnate leaves, up to 6 inches (15.2 cm) in length, terminating with several pairs of leaflets with saw-toothed margins; they can grow up to 16 inches (40 cm) long. Leaflets are arranged in pairs along the stalk. Lower leaves have short stems, upper leaves are stemless. The leaves give off a pungent odor when crushed. During the vegetative growth season, wild parsnip continuously produces and loses leaves. The flower stalk develops from the rosette in the second year and can grow to a height of 4 – 5 feet (123 – 150 cm). It is grooved, hairy, and, except at the nodes, hollow. The stalk is sparsely branched. Over the winter above ground wild parsnip plants die back with only one or two leaves remaining on each plant.

 

 

Each wild parsnip plant produces hundreds of small yellow flowers which bloom from June to mid-July. The flowers are arranged in a loose compound umbel (a structure made up of a number of short flower stalks which spread from a common point, looking like the ribs of an umbrella). An umbel can measure from 4 – 8 inches (10 – 20 cm) in diameter. The flowers consist of five yellow petals curled inward, five stamens, and one pistil. The large, straw to light-brown seeds that are produced by the flower heads are round to oval, flat, slightly ribbed with narrow wings and are 1 ½ – 3 inches (4 – 8 mm) long. Seeds mature by early July. Plants die after producing seeds; the dead stalk will remain standing through the winter. Seeds can remain viable in the soil for four years. Seedling mortality is high; less than 1% of seedlings survive to mature and reproduce.

 

Impacts

Ecological Impacts:

Wild parsnip invades and modifies disturbed open habitats. Well-established fields and meadows are not likely to be invaded, but parsnip can become well-established along the edges and in disturbed areas. Once an infestation begins, it can spread into adjacent areas and form dense stands in high-quality fields and meadows. Wild parsnip is also very persistent on sites that remain disturbed or bare such as paths, roadsides, and utility rights-of-way.

Human Health Impacts:

While wild Parsnip roots are edible, the plant produces a compound in its leaves, stems, flowers, and fruits that causes intense, localized burning, rash, severe blistering, and discoloration on contact with the skin on sunny days. This condition, known as phytophotodermatitis, is caused by furanocoumarin contained in the sap. This is not an allergic reaction, it is a chemical burn brought on by an increase in the skin’s sensitivity to sunlight. Affected areas can remain discolored and sensitive to sunlight for up to two years, similar to but not as severe as contact with giant hogweed. This reaction is not brought on by contact with the foliage of the plant, only by contact with the sap.

Contact may occur when working, hiking, and harvesting crops, including when visiting u-pick operations. To reduce the risk of exposure to wild parsnip sap, when undertaking such pursuits one should wear long-sleeved shirts, gloves and long pants.

If one should come in contact with wild parsnip sap, you should immediately cover the exposed skin to prevent the reaction to sunlight (but the area will remain sensitized for about eight hours). The contact area should be washed with warm water and a mild soap. If exposure to sunlight causes a burn and blisters to develop the affected area should be covered with a cool, damp cloth to help relieve pain. The blistered skin should be kept out of the sunlight to avoid further burning. If blistering is severe, see a physician. There is no cure for parsnip burns; however, a topical or systemic cortisone steroid may relieve discomfort.

 

The essential oil of parsnip roots contains a large percentage of Myristicine, a strong human hallucinogen.

Wild parsnip is regulated in Ohio, Illinois, Tennessee, and Wisconsin.

Prevention of Establishment & Spread

Remove new infestations while they are still small. Avoid mowing areas with wild parsnip when viable seeds are present as equipment readily spreads seed to new areas. Clean mowing equipment before moving from an area with wild parsnip to one without. When possible, plan to harvest/mow areas without wild parsnip before moving to fields where it is present. Time control efforts to prevent spread of the plant.

Control & Management

Management decisions should be based on the quality of the area, the degree of the infestation, and use of the infested area by people or livestock.

Manual control for small patches is effective. Cut the root 1” below the ground using a tool such as a spaded shovel or remove plants by hand pulling, gripping the stalk just above the ground. These control measures should be undertaken before wild parsnip plants go to seed. If hand pulling after seed formation, take steps to destroy the seeds. For small areas which have set seed, cut the tops with clippers, bag the seed heads in clear plastic and allow to rot.

Mowing – Mow when plants first produce flowers, but before seeds enlarge. At this stage plants have depleted their root resources and often die when cut. Some plants will re-sprout, so a follow-up mowing may be needed. When using any type of mowing equipment, take precautions to prevent plant sap from contacting exposed skin. Mowing can tend to favor wild parsnip rosettes as more sunlight is able to reach them, as well as reducing the number of plants competing with them for light and nutrients.

Chemicals – General-use herbicides such as glyphosate or triclopyr can be applied as spot treatments to basal rosettes. Be sure to follow all label and state requirements.

Biocontrol – No effective options are currently known. The parsnip webworm infests individual plants, but is not known to significantly damage large patches.

Plan to monitor the area long-term for seedlings emerging from the seed bank.

Whatever type of control method is employed, make certain to take measures to protect skin and eyes from contact with the plant’s sap.

New York Distribution Map

This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.

Background  |  Origin and Expansion  |  Biology  |  Characteristics and Identification  |  Impacts  |  Prevention, Control, and Management  |  New York Distribution Map

Background

Mugwort  (Artemesia vulgaris) is an invasive perennial forb that is widespread throughout North America, though it is most common in the eastern United States and Canada. It is a weed of nurseries, turfgrass, vineyards, waste areas, forest edges, and roadsides. Mugwort spreads aggressively through an extensive rhizome system and will readily form large, mono-specific stands.

Origin and Expansion

Mugwort is native to Europe and eastern Asia, where it has historically been used as a medicinal herb. Seed may have been first introduced to North America as early as the 16^th century by Jesuit missionaries in Canada. It was also introduced throughout the continent as a contaminant in ship ballast and nursery stock.

Biology

Mugwort is a perennial with an extensive rhizome system. Shoots emerge during the spring, and flowering occurs from July to late September. A single plant can, depending on its environment, produce up to 200,000 seeds.  The small seeds (~1mm in diameter) are largely wind dispersed. Seed production does not seem to be a major factor in the spread of mugwort populations, however, and some biotypes do not produce viable seed.  Instead, mugwort spreads largely through vegetative expansion and the anthropogenic dispersal of root propagules. The root system is extensive though shallow (to 20 cm in depth), with numerous branching rhizomes up to 1 cm in diameter. Plants can regenerate from rhizome fragments as small as 2 cm (Klingeman et al. 2004).

Characteristics and Identification

The rarely-seen seedlings have oblong cotyledons without petioles. Adult stems are smooth and longitudinally ridged, with numerous axillary branches towards the upper portions of the plant. The stems become somewhat woody as they age. The leaves are alternate, densely covered with wooly, silver-white hairs on the underside, and slightly hairy on the upper surface. Leaf morphology is variable throughout the plant. The lower leaves are petiolate, with stipules at the base, and generally coarsely toothed and pinnately lobed. The upper leaves are sessile and lanceolate with smooth or toothed margins. The numerous ray and disk flowers are small (5 mm), green, and grow in racemes and clusters at the end of stems and branches. The foliage is aromatic and slightly pungent.

Impacts

Mugwort is a problematic weed in nurseries, where small root fragments can easily contaminate nursery stock. It is also a major weed in turf grass, field-grown ornamental crops, and orchards. Stands of mugwort displace native species, and can delay or disrupt succession in natural ecosystems (Barney and DiTommaso 2003). Mugwort produces several terpenoid potential allellochemicals, and decaying mugwort foliage has been shown to inhibit the growth of red clover in laboratory experiments (Inderjit and Foy 1999). Mugwort pollen is a common cause of hay fever.

Prevention, Control, and Management

The dense root system of mugwort can make it difficult to control. Pulling is ineffective, and may even promote growth by leaving residual rhizome fragments in the soil. Mugwort tolerates mowing, and even sustained mowing over two years will not fully eradicate mugwort stands. The relatively shallow roots make mugwort vulnerable to repeated cultivation in agricultural systems, though this practice risks spreading root propagules.

Chemical control of mugwort can have limited effectiveness. Though non-specific broadleaf herbicides such as glyphosate or dicamba can effectively control mugwort, the rates required for adequate suppression are rarely economical (Bradley and Hagood 2002). For small infestations, multiple spot-treatments of glyphosate can be effective (Bing 1983).

New York Distribution Map

This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.

Background | Origin | Habitat | Introduction and Spread | Impacts | Identification | Prevention and Control | Occurrences | New York Distribution Map

Background

Norway maple (Acer platanoides) is a large deciduous tree that can grow up to approximately 40-60 feet in height.  They are tolerant of many different growing environments and have been a popular tree to plant on lawns and along streets because of their hardiness.  Norway maples have very shallow roots and produce a great deal of shade which makes it difficult for grass and other plants to grow in the understory below.  Additionally, they are prolific seed producers and are now invading forests and forest edges.

Origin

Norway maples are native to Europe and Western Asia.

Habitat

Norway maples are found growing all over the United States in many diverse environments. They are very well adapted to extreme soil types and found in hardy to USDA Zone 4. Norway Maples tolerate a wide range of temperatures. They do prefer full sun, but may also be seen in shady habitats. Also, this species is tolerant to sulfur dioxide pollution and ozone, so they can thrive in urban settings or forests. Norway Maples will be found in the United States anywhere from the border of Canada south to the Carolinas in early or late succession forests, wetlands, yards or gardens, or in disturbed open areas and roadsides.

Introduction and Spread

Many Norway maples made their way from Europe to the United States by being transplanted as ornamental specimens or by having individual seeds escape cultivation. These trees produce ample amounts of winged seed which are dispersed readily in the wind and germinate quickly. A suggested reason for the success of many invasive species is the absence of predators in the invaded habitat. A study by Cincotta et al. (2009) found that foliar insect and fungal damage was significantly higher on native sugar maples than on the invasive Norway maples. This could be one of the contributing factors to the Norway maple’s success.

Impacts

Forests that are intact are generally more likely to ward off invaders. However, Norway maple has been found to be very successful at establishing itself in a variety of conditions including mature, deeply shaded forests (Martin and Marks 2006). Due to the dense canopy of Norway maples, forest diversity is starting to decline because the excess shade they create inhibits the regeneration of sugar maples and other native seedlings. The shallow root system makes growing difficult for other native shrubs and wildflowers in the understory. In urban environments, the root systems also destroy pavement, requiring expensive repairs. Other species of flora and fauna, such as insects and birds, may indirectly be affected due to the change in resource diversity and availability. Norway maple is also susceptible to certain types of fungi, such as Verticillium wilt and anthracnose and may also serve as a host for aphids.

Identification

Norway maples have simple, green, and opposite leaves. Leaves of Norway maples usually are broader than they are high, about four to seven inches wide, with five prominent lobes. The bark of a Norway maple is grayish black and furrowed. This species tends to leaf out earlier in the spring than other maples and forms a broad-rounded crown. Yellow or greenish-yellow flowers are approximately 8 mm in diameter and are found in clusters that are present from April to May. During the summer, fruits mature into helicopter-like blades with wide-spreading wings. In the fall, leaves usually turn a pale yellow. One of the easiest ways to differentiate Norway maple from sugar maple is to cut the petiole (or leaf stalk) or vein and if a milky substances oozes out, it is a Norway maple.  Also, bud tips of Norway maples are more blunt, whereas sugar maples are pointy and sharp.

Prevention and Control

It is recommended to plant alternative tree species that are native to this region to prevent further spread of Norway maple. Other maple species that are native to the Northeastern United States include red maple (Acer rubrum), sugar maple (Acer saccharum), and silver maple (Acer saccharinum).

Seedlings of Norway maple can be pulled from moist soil before they get too large. Other types of manual removal include digging out saplings and root systems or cutting down large trees. Girdling the trees by removing the bark layer (including the cambium) can also be performed, but is most effective in the spring. Leftover stumps can be ground out or new growth that develops from old stumps can be cut in future years. Some chemical herbicides, such as glyphosate or triclopyr may be useful for control, but contact your local extension office for more information on chemical application and always follow state requirements and the instructions on the label.

Occurrences

Norway maple is found on both the western and eastern sides of the United States. It ranges from Canada in the north and down south to the Carolinas.

New York Distribution Map

This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.