Rhamnus frangula L.

Common Name: Glossy buckthorn

Synonyms and Other Names:

Rhamnus frangula L., Rhamnus frangula var. angustifolia Louden, columnar buckthorn, European alder, fen buckthorn, tall hedge buckthorn, alder buckthorn



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Identification: Frangula alnus is a shrub or small tree with brownish gray bark speckled with easily distinguished elongated, lighter areas called lenticels (Michigan Natural Features Inventory 2012). Bark may be shallowly fissured on larger stems. If a branch is cut, the sapwood (tissue just below the outer bark) is yellow and the heartwood (tissue in the center) is pink/orange (Michigan Natural Features Inventory 2012). When young, glossy buckthorn has multiple stems. As it matures it develops a trunk that may reach 25 cm in diameter (Michigan Natural Features Inventory 2012). Young stems and branches appear greenish-brown with tiny hairs (Michigan Natural Features Inventory 2012).

The leaves grow alternately along branches, but may appear opposite toward the tips (Michigan Natural Features Inventory 2012). The thin, elliptic to oblong leaves are shiny green from above and pale green from below (Michigan Natural Features Inventory 2012). Leaf edges are smooth, and there are 8 or 9 pairs of parallel veins that curve up toward the tip of the leaf (Michigan Natural Features Inventory 2012, NRCS 2007). Leaves stay green or turn slightly yellow before they senesce in early winter (NRCS 2007).

The bell-shaped flowers are very small, have five pinkish white petals, and are fragrant (NRCS 2007). Flowers appear in clusters of 2-8 at the bases of the leaves (Michigan Natural Features Inventory 2012). The flowers contain both male and female parts and are in bloom from late May through September (Michigan Natural Features Inventory 2012).

The fruit is a round drupe, about the size of a pea (Michigan Natural Features Inventory 2012). Fruit can be found between July and September; it starts green, turns red, and then changes to dark purple/black as it ripens (Michigan Natural Features Inventory 2012). Ripe and unripe fruits may be present on the same tree (NRCS 2007).

In the winter, branches have a bumpy silhouette from leaf scars and terminate in rust colored buds (Michigan Natural Features Inventory 2012, WIDNR 2008).


Size: 6-7 m (NRCS 2007)


Native Range: Eurasia


Map Key
This map only depicts Great Lakes introductions.

 
Great Lakes Nonindigenous Occurrences: First Great Lakes record: 1913, Lake Ontario (USEPA 2008)


Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Rhamnus frangula are found here.

State/ProvinceFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
IN198519892Little Calumet-Galien; St. Joseph
MI1933202149Au Gres-Rifle; Au Sable; Bad-Montreal; Betsie-Platte; Betsy-Chocolay; Black-Macatawa; Black-Presque Isle; Boardman-Charlevoix; Brule; Cedar-Ford; Cheboygan; Clinton; Dead-Kelsey; Detroit; Escanaba; Fishdam-Sturgeon; Flint; Huron; Kalamazoo; Kawkawlin-Pine; Keweenaw Peninsula; Lake Erie; Lake Huron; Lake Michigan; Lake St. Clair; Lake Superior; Little Calumet-Galien; Lone Lake-Ocqueoc; Lower Grand; Manistee; Manistique River; Menominee; Muskegon; Northwestern Lake Michigan; Ontonagon; Ottawa-Stony; Pere Marquette-White; Pigeon-Wiscoggin; Raisin; Saginaw; Shiawassee; St. Joseph; St. Joseph; Sturgeon; Tacoosh-Whitefish; Thornapple; Thunder Bay; Tittabawassee; Upper Grand
MN201620161Beaver-Lester
OH201120183Chautauqua-Conneaut; Grand; Lower Maumee
VT199920172Otter Creek; Winooski River
WI197520199Bad-Montreal; Beartrap-Nemadji; Brule; Door-Kewaunee; Menominee; Oconto; Peshtigo; Pike-Root; Wolf

Table last updated 3/28/2024

† Populations may not be currently present.


Ecology: Frangula alnus has a high level of phenotypic plasticity; it is able to alter its physical appearance based on environmental conditions. Individuals may appear as shrubs, small trees, or some combination thereof (WIDNR 2008).

Frangula alnus is typically found in wet environments: marshes, bog, fens, along shorelines, and ditches (Ohio EPA 2001, State of Minnesota 2009). This species can also be found in drier environments such as woodland edges and old fields, and disturbed areas such as along roadsides, fences, powerlines and pathways (Campbell et al. 2010, Ohio EPA 2001, Reznicek et al. 2011). It will survive in both full sun and full shade, but fruit production might be slowed for those individuals growing in full shade (State of Minnesota 2009). It is often a woody pioneer species in drained mires and conveyed wet meadows. Buckthorn species grow rapidly and will resprout when damaged (naturally or mechanically) by up to 2.5 meters (Larson 2009, WIDNR 2008).

Leaves of glossy buckthorn emerge early in spring and remain green on the trees until late fall or early winter (PADCNR n.d.). This species reproduces sexually (it cannot self fertilize) and is pollinated by insects (Borland et al. 2009, Michigan Natural Features Inventory 2012). Glossy buckthorn is typically in bloom from late May until the first frost (WIDNR 2008). It produces fruit from early July through September, and it is not uncommon to see both flowers and fruit (in all stages of ripening) on a single plant (Borland et al. 2009, WIDNR 2008).

Its fruit is eaten by a variety of birds and mammals. Given their cathartic properties, seeds spend little time in the digestive track and often remain viable (Campbell et al. 2010, GLC 2006). Ripe fruits are buoyant for up to two weeks and can be transported through waterways (NRCS 2007, PADCNR n.d.). Fruit that is transported via waterways or dropped directly onto the soil can remain viable for 5-6 years (NRCS 2007, State of Minnesota 2009).


Means of Introduction: Deliberate release - Frangula alnus was introduced to North America prior to the 1900s for horticultural purposes as hedges and specimens for landscaping because of its hardiness and absence of pests (Haber 2001).

Frangula alnus seeds are efficiently dispersed usually by starlings, blackbirds, woodducks, elk, mice (Ridley 1930), cedar waxwings, robins and blue jays. Mice are also seed predators (Godwin 1936).  Berries of F. alnus are eaten by American robins, Bohemian waxwings, cedar waxwings, rose-breasted grosbeaks, and starlings. The shrub probably has a number of different avian and mammalian dispersal agents.


Status: Established


Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...

EnvironmentalSocioeconomicBeneficial



 

Frangula alnus has a high environmental impact in the Great Lakes.
Realized:
Frangula alnus leafs out early in spring and retains its leaves late into the fall (Ohio EPA 2001, PADCNR n.d.). The leaves remain photosynthetically active until they fall from the plant, allowing glossy buckthorn to out-compete native trees, shrubs, and wildflowers for light (GLC 2006, NRCS 2007, State of Minnesota 2009). As a result, monocultures are formed, which harms songbird habitat and shifts the plant community to one that is more shade tolerant (NRCS 2007, Roman 2007). Along with changing the amount of available light, glossy buckthorn also uses allelopathy to alter the plant community around it (PADCNR n.d.). The extensive root system of F. alnus allows it to out-compete native plant for nutrients and water (Ohio EPA 2001, State of Minnesota 2009).

Glossy buckthorn threatens the current ground vegetation and prevents oak seedling growth in oak savannas, an endangered ecosystem in the Midwest (Mills 1993 in Pleasant Valley Conservancy 2012; Reid and Holland 1997). In Gavin Bog, Illinois, F. alnus has displaced Ilex verticillata, a species native to the Great Lakes (Taft and Solecki 1990 in Frappier et al. 2003).

In Indiana, glossy buckthorn has invaded the understory and reduced the diversity of native plants crucial to native wildlife (Illinois Natural Heritage Database 2011). Frangula alnus has invaded various wetland ecosystems in Wisconsin and shaded out native plants as a result (Thompson and Luthin 2004). Sinclair and Catling (1999 in Frappier et al. 2004) found that the presence of F. alnus in wetlands in Ontario reduced species richness and that when removed, the density of native plants increased. However, Possessky et al. (2000 in Frappier et al. 2004) found that in savanna ecosystems in Pennsylvania the species richness was higher in areas were F. alnus was present. Mills et al. (2009) also found little change in the resident plant community after glossy buckthorn was allowed to grow and expand freely into the study site.

European starlings, rose-breasted grosbeaks, cedar waxwings, and American robins, all of which have at least part of their range in the Great Lakes, feed on the fruits of glossy buckthorn (Michigan Natural Features Inventory 2012). Small mammals, such as rodents, also feed on this berries (NRCS 2007). However, consuming these berries often leads to a net energy loss due to their diarrheic qualities (Czarapata 1999 in Falck and Garske 2002).

Frangula alnus is a winter host to the introduced pest soybean aphid, Aphis glycines (NRCS 2007). Soybean aphids have been collected from F. alnus in Springfield Fen, Indiana (Hill et al. 2010).

Potential:
Frangula alnus may be a competitive threat to two endangered Rhamnus spp. in the Great Lakes: R. alnifolia (endangered in Illinois) and R. lanceolata (endangered in Pennsylvania) (PLANTS Team 2012).

If glossy buckthorn becomes a dominant species in an ecosystem, the ability of a forest to regenerate and continue through the steps of succession may become severely limited (Forest Health Staff 2006). Dense patches of glossy buckthorn may also contribute to erosion by shading out other plants that grow on the forest floor (State of Minnesota 2009).

Buckthorns are often found in soils with higher nitrogen content, although it is unknown if this is due to initial establishment conditions or if they alter the surrounding soil chemistry via their leaf litter. This also makes the surrounding soil environment more favorable for exotic earthworms. Exotic earthworms are known to alter soil characteristics by increasing carbon, nitrogen, pH, and moisture, as well as by modifying the microbial community (Roman 2007).

There is little or no evidence to support that Frangula alnus has significant socio-economic impacts in the Great Lakes.
Realized:
Fruit from F. alnus will stain houses, cars, patio furniture, sidewalks, etc. (State of Minnesota 2009).

Potential:
Eastern white pine (Pinus strobes) forests invaded by F. alnus may become less valuable for logging as glossy buckthorn spreads and prevents these trees from regenerating (Fagan and Peart 2004).

Horses may become poisoned if allowed to consume F. alnus (van den Dikkenberg and Holtkamp 1987).

Frangula alnus has a moderate beneficial effect in the Great Lakes.
Realized:
In some areas glossy buckthorn is still sold in nurseries in two different forms: ‘Columnaris’ and ‘Asplenifolia’ (Michigan Natural Features Inventory 2012). Many homeowners appreciate dense thickets of F. alnus because it provides privacy (Larson 2009).

Glossy buckthorn provides attractive wood that can be used to build trellises, carved into walking sticks, or used in artwork (Larson 2009). The wood also burns slowly, making it a good choice for firewood (Larson 2009).

This species provides cover and nesting space for a variety of birds for a longer period of time than native species. However, species nesting in glossy buckthorn can be more susceptible to predation because glossy buckthorn lacks the protective thorns of many native shrubs (Roman 2007).
Extracts of F. alnus, often in combination with other plants, have been used in laxatives for humans. Matev et al. (1981) reports that the combination of F. alnus, Citrus aurantium, and Carum carvi was an effective laxative in 100% of the subjects.

Potential:
Anthraquinones extracted from F. alnus successfully inactivated the herpes simplex virus type 1 in laboratory experiments (Sydiskis et al. 1991).

Methanol extracts of F. alnus may have anti-fungal properties (Manojlovic et al. 2005).

Frangula alnus is able to accumulate manganese and may be useful is soil remediation (Alvarez et al. 2003).


Management: Regulations (pertaining to the Great Lakes)

The New York Invasive Species Council assessed F. alnus as having a high risk of causing ecological harm and recommended that its use be prohibited (New York Invasive Species Council 2010). This species is restricted in Wisconsin; it may not be transported, transferred, or introduced into any ecosystem (Bureau of Plant Industry 2012). Frangula alnus is considered an exotic weed by the Illinois Department of Natural Resources; sale of this species within the state is not allowed (Bureau of Environmental Programs 2009). It is listed as a restricted noxious weed in Minnesota and the importation, sale, or transport this plant is illegal (State of Minnesota 2009).

This species is not widespread in the ceded territories governed by the Great Lakes Indian Fish and Wildlife Commission (GLIFWC). The GLIFWC recommends that glossy buckthorn be controlled immediately upon being found. In areas where F. alnus is already present, the GLIFWC categorizes it as capable of having severe ecological impacts and recommends that small, peripheral populations be controlled upon detection and center populations be monitored (Falck and Garske 2003).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

When treating a large infestation and/or working with limited resources, priority should be given to the largest trees bearing blooms or fruits (Thompson and Luthin 2004). It is important to have a disposal method in place for the portions of the glossy buckthorn that contain fruit. Stems and branches with berries can be destroyed by burning; those without fruit can be left on site to decompose (NRCS 2007). If burning is not an option, fruit should be disposed of off-site (PADCNR n.d.).

Biological
Currently there are no specific biological control agents for this species, but research on more generalized herbivores is ongoing (Chandler et al. 2010).

Physical
Cutting alone will not control this species because it will resprout, regardless of what time of year it was cut (IPAW 2012). When using a physical control method, effort should be made to limit soil disturbance so as not to cause to erosion (Larson 2009).
Individual plants less than 0.5 inch in diameter can be removed by hand. Removing manually is easiest when the soil is sandy or is moist (Michigan Natural Features Inventory 2012). Care must be taken to disturb the soil as little as possible (Buenzow 2010). Plants that are 0.5 inch to 1.5 inch in diameter can be physically removed with a mechanical device- care should be taken to disturb as little of the soil as possible (Buenzow 2010).

Glossy buckthorn can also be controlled through girdling. In this method, cuts are made to the trunk or main stem just above the base, the bark is removed (including the green, cambium layer beneath the bark) (NRCS 2007). The cut should be large enough, about an inch long, to prevent the tree from healing (NRCS 2007). The Illinois Natural History Survey recommends making 2 parallel cut 4-5 inches apart when girdling (Heidorn 2011). This method is most effective when in the summer after the leaves have fully developed or after the leaves have dropped off in the early winter (NRCS 2007). This method is less effective on plants that have many main trunks/main stems (NRCS 2007).

If glossy buckthorn is growing in a grassland or savanna ecosystem, controlled burns may offer long-term control. This method needs to be repeated ever 2-3 years (State of Minnesota 2009). Burns are most effective from April through June and from September through November (Hanson et al. 2012).

Repeated mowing in open areas has been reported to be effective in prevented seedling establishment (Ohio EPA 2001). This method is most effective for plants less than 2 years old. Mowing in early spring and again in fall will help deplete the energy reserves in the root system, deplete the seed bank, and will not interfere with any birds that may use glossy buckthorn for nesting (NRCS 2007).

If glossy buckthorn is present in a managed wetland with a lowered water level, returning the level to its original depth may flood and kill the plants. The impact a changed water level will have on the whole ecosystem should be determined in advance (Roman 2007).

Chemical
Adding dye to herbicides prior to application, will help distinguishes between plants that have and have not been treated (Michigan Natural Features Inventory 2012).

One method is to spray foliage with herbicides such as glyphosate (Accord®, Foresters’ Glypro®, Roundup®, Cornerstone®, Razor®), triclopyr (Garlon 3A®, Garlon 4®, Tahoe 4E®), fluazifop (Fusilade II®), imazapyr, metsulfuron-methyl, 2,4-D, or picloaram to control glossy buckthorn (Division of Forestry 2011, Hanson et al. 2012). Glyphosate will kill any vegetation it comes in contact with and triclopyr will kill broadleaf plants, but will not harm grass if applied properly (State of Minnesota 2009). The best time to use the foliage spray method is between May and November (Hanson et al. 2012).

For plants with stems less than 6 inches in diameter, basal steam treatment, in which an oil-based herbicide is applied directly the bark from the root collar up 12-18 inches, can be used without having to cut down the plant (Buenzow 2010, State of Minnesota 2009). Glyphosate and triclopyr can also be used for this technique (Hanson et al. 2012). Herbicide can be applied with a low-pressure backpack sprayer. Herbicide can be applied any time of year, providing there is access to the ground line; although late fall and winter are preferred because plants are dormant. Glossy buckthorn may leaf out in the spring after a fall or winter herbicide application, but the leaves should senesce as the chemicals are translocated throughout the plant (Buenzow 2010). Basal spraying is the most cost-effective method of controlling populations of glossy buckthorn (Thompson and Luthin 2004).

Both the ester and amine formulations of triclopyr can be used to treat glossy buckthorn; the amine form is safe for use in most wetlands (Larson 2009, Michigan Natural Features Inventory 2012).

Other
Larger trees can be cut near soil level in late summer or early fall. The stumps should then be treated within two hours of being cut with herbicides containing triclopyr. Only the cut surface needs to be treat when using a water-soluble herbicide, but when using an oil-based herbicide, treat the cut surface and the remaining bark (State of Minnesota).

For more detailed information please see:

Midwest Invasive Plant Network Invasive Plant Control Database

The Michigan Department of Natural Resources- Best Control Practices for Glossy Buckthorn
http://mnfi.anr.msu.edu/invasive-species/GlossyBuckthornBCP.pdf

The Pennsylvania Department of Natural Resources- Invasive Exotic Plant Tutorial
http://www.dcnr.state.pa.us/forestry/invasivetutorial/common_glossy_buckthorn_M_C.htm

The Natural Resource Conservation Service- Pest Management for Buckthorn
http://efotg.sc.egov.usda.gov/references/public/MN/797Buckthorn.pdf

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.


Remarks: Buckthorn taxonomy has been historically controversial. However, more recent genetic research supports the separation of Frangula species, including glossy buckthorn, from the Rhamnus genus (Bolmgren and Oxelman 2004).  This change is not yet in ITIS, but has been adopted by USDA.  


References (click for full reference list)


Author: Sturtevant, R., L. Berent, and A. Fusaro


Contributing Agencies:
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Revision Date: 7/28/2022


Citation for this information:
Sturtevant, R., L. Berent, and A. Fusaro, 2024, Rhamnus frangula L.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=2697&Potential=N&Type=0&HUCNumber=DHuron, Revision Date: 7/28/2022, Access Date: 3/28/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.