Rhamnus cathartica

From Bugwoodwiki

Authors: Carmen K. Converse, Global Invasive Species Team, The Nature Conservancy

R. cathartica
Scientific Name
Rhamnus cathartica
Common Names
European buckthorn, common buckthorn, European buckthorn


Rhamnus cathartica is a deciduous shrub or small tree that can grow to 25 ft. (7.6 m) in height. The bark is dark gray and the inner bark is orange (easily seen when the tree is cut). Twigs are usually tipped with a sharp spine.
The leaf arrangement is usually sub-opposite, but examples of opposite and/or alternate arrangements are commonly found. Leaves are dark green, oval, 1.5-3 in. (3.8-7.6 cm) long, slightly serrate with 3 to 4 pairs of curving veins and a somewhat folded tip.
Flowering occurs in the spring, with fragrant, yellow-green, 4-petaled flowers developing in clusters of 2 to 6 near the base of the petioles. Plants are dioecious (male and female flowers occur on separate plants).
Appearing in the fall, the small, purple to black fruit are 0.25 in. (0.6 cm) in diameter. The fruit contains 3-4 seeds. Birds and other wildlife eat the fruit and disperse the seeds.
Ecological Threat
Rhamnus cathartica invades forests, prairies, and savannas in the Midwestern United States and can form dense thickets crowding out native shrubs and understory plants. It is difficult to remove and can regenerate after cutting or burning. It is a native of Europe and was introduced into the United States as an ornamental shrub.




R. cathartica is native to most of Europe except Iceland and Turkey; and grows in west and north Asia. R. frangula is native to North Africa, Asia, and Europe, except Iceland.[1][2]

In North America, R. cathartica is naturalized from Nova Scotia to Saskatchewan, south to Missouri and east to Virginia.[3]

Native Habitat (Europe/Asia): Native habitats of R. cathartica are diverse and include the understory of open oak [4][5], oak beech, or ash woods.[4][6] It also occurs in riverine woods [4][5], thickets on exposed rocky sites [6], hedgerows [1][7], pastures (Tansley 1968)[1][8] and alkaline shrub carr fens ( Tansley 1969).[9] It grows in well drained sand, clay, or poorly drained calcareous soils, but prefers neutral or alkaline soils. It is less vigorous in dense shade, and may grow on woodland edges in sunny southern or western exposures.[5]

North America: This species was probably introduced to North America before 1800 [10], but did not become widespread and naturalized until the early 1900s.[11] It is cultivated for hedges [10], forestry uses, and wildlife habitat. R. cathartica is used in shelter belt planting.[12] Naturalized habitats include pastures, fencerows, roadsides, and slopes of ravines.


Natural reproduction is primarily sexual; asexual means are absent or insignificant.

Plants reach seed bearing age quickly.[13] Flowers of R. cathartica may be polygamous, but are usually dioecious [14] and bloom May through June during leaf expansion.[15]

The globose black drupes of R. cathartica ripen in August through September, and each contains three or four grooved seeds. Fruit production is abundant each year [12], but R. cathartica is apparently more productive than some other buckthorns.[16][17]


Fruit is efficiently dispersed usually by starlings, blackbirds, woodducks, elk, mice [18], cedar waxwings, robins and blue jays. Mice are also seed predators.[13] Apparently, few bird species readily tolerate the anthranquinones (emodin) present especially in the immature fruit, preventing premature dispersal (Trail and Dimond 1979). R. cathartica retains fruit into, or throughout, the winter.[13]

Because R. cathartica fruit is retained on the plant longer and is therefore more visible to birds, seeds may be dispersed more frequently over longer distances than seeds from other species like R. frangula.

The importance of water dispersal is unknown, but dry fruit of R. cathartica can float six days and seeds float three days before sinking. This dispersal could be significant in areas of frequent and extensive fall and winter flooding.

Horticultural distribution increases seed sources for dispersal by the above vectors.


Germination varies because seeds have either embryo or seed coat dormancy or both require stratification and scarification.[19][12][13] This variability is not necessarily consistent within a species [12] such that germination could be opportunistic.

Seedling Establishment:

Although seedlings invade apparently stable habitats, recruitment is most successful where there is ample light [5][20] and exposed soil.[21] Tests of R. cathartica seedlings grown under various densities and light intensities showed reduced growth as shade increased.[5] In a reforestation project, seedling success was greater in areas where previous vegetation was removed and soil cultivated, than in areas burned, lightly raked, or untreated prior to seedling (Bodeux 1958).

These buckthorns have long growing seasons, rapid growth rate, and resprout vigorously following top removal. Alteration of dormancy growth rhythms in Buckthorns is not significantly related to thermo or photoperiods.[22] In North America, they leaf out prior to most woody deciduous plants - in late April to mid May. They retain leaves in late September through October and sometimes into November.[16][23] Leafdrop possibly occurs earlier in open areas than in shade.[24]

Buckthorns rapidly form dense, even aged thickets. In an open site, buckthorn establishment is followed by lateral crown spread. This extension continues until branches touch adjacent shrubs. The large leaves and continuous canopy create dense shade. Even aged thickets are common in both wetlands and in woodland understories.

The vigor of the species is often related to light availability. It seems that seedlings of R. cathartica establish readily under partial light. As plants mature, other Buckthorns show less shade tolerance than does R. cathartica. For example, it shades out its lower leaves and assumes a more columnar growth habit in dense thickets, while R. cathartica may retain lower leaves in its own shade.[13] Seedlings may become established, but show little growth under adult plants. Thickets may be even aged because seedlings are repressed.

Buckthorn affects the survival of co occurring species. Other woody plants such as Viburnum opulus L. (in Europe) and Betula pumula L. may be replaced by buckthorn, or are unable to invade buckthorn thickets.[25][13]

The effects of buckthorn on herbaceous vegetation is uncertain. In Wicken Fen, dense thickets of both species altered herbaceous understory composition.[26] In an oak woods study, R. cathartica did not significantly alter herbaceous ground cover composition, but did limit growth of other woody seedling species.[5][27]


Management problems:

In addition to the above naturalized habitats, these species are problems in parts of some natural areas. R. cathartica invasion is greatest in selectively cut or grazed woods [5], along woodland edges, in openings created by windfalls or deadstands because of canopy tree disease [28] or in thickets growing within prairies.[29] Open oak woods[30][29], and lowland woods [31] are typically invaded; sugar maple woods are less frequently invaded.[5] Fire suppression along the prairie forest border has possibly increased invasion in open woods and adjacent prairie.[5] R. cathartica tolerance of heavy clay soils, and moist or dry sites increases its success in some of the above habitats.

Other possible reasons for invasion of wetlands include:
1. Acidification of surface peat of calcareous fens.[26]
2. Exposed mineral soil providing a seed bed.[21]
3. Fire supression and cessation of routine mowing.[32][33][34][35][13][26][36][37]

Composition, especially of upland deciduous woods and of wetlands may be altered because of invasion of R. cathartica. This species is invasive for the following reasons:

1. They became widespread in North America when various disturbances (drainage, lack of fire, woodland grazing and cutting, etc.) created ideal habitat for seedling recruitment and maintenance of sexually mature adults.
2. Naturalized habitats are similar to indigenous habitats.
3. Seed production, dispersal and germination are effective.
4. Adult plants form dense colonies, have large shading leaves, and are persistent.
5. Plants vigorously resprout after top removal.

Cultural controls include cutting, mowing, girdling, excavation, burning, and "underplanting."


Repeated cutting reduces plant vigor. In one case, techniques of double cutting within several hours of the same day did not control growth of R. cathartica.[38] Mowing maintains open areas by preventing seedling establishment.[13][37]


Girdling may be done all winter, does not disrupt the soil, nor adversely affects sensitive wetlands. A five second flame torch application around the stem will kill the cambium of stems less than 4.5 cm in diameter.[39]


Seedlings or small plants may be hand pulled or removed with a grubbing hoe [29][27][40][21] or larger plants may be pulled out with heavy equipment.[27][41] Excavation often disturbs roots of adjacent plants, or creates open soil readily colonized by new seedlings.[40] This technique may be most useful to control invasion at low densities, or along trails, roads, and woodland edges.


Presently most fire treatments do not control Buckthorn. Some data indicate limited effective use of fire management in a recovery phase. The season of a burn and vegetation of the area to be burned most influence this phase of fire management. Because Buckthorns leaf out earlier than most native species, a late April or early May burn in the upper midwest (Wisconsin, Illinois, Michigan) potentially top kills Buckthorn. Because carbohydrate levels are low in roots at this time, resprouting vigor may be reduced.

If herbaceous vegetation exists beneath buckthorns, fire effectively top kills shrubs especially during dry weather.[13] In most cases, however, groundcover is sparse beneath large shrubs or dense thickets, preventing fire spread unless conditions are dry and/or windy.[42] Resprouting usually follows top kill, especially in wetlands where moisture protects the basal crown.[13] Harty (1983)[43] found that burning an oak savanna on a two year rotation for R. cathartica control resulted in resprouting.

A burning schedule to maintain vigor of native vegetation possibly prevents easy seedling establishment, unless seed sources are nearby.

If seed sources are near burned areas, fire exposed soils or peat probably are more readily invaded by seedlings than groundcover of unburned areas.[44] In some wetlands, lack of flooding following burning has been shown to increase general woody plant invasion.[34]


"Underplanting" disturbed woods with native woody species is potentially effective to prevent primary invasion, or re invasion of buckthorns. Sugar maple (Acer saccharum Marsh.) seedlings have been planted in oak woods of the Morton Arboretum Illinois [30], and the University of Wisconsin Arboretum.[29] Seedling success was poor in the Illinois planting. In Wisconsin, sugar maple that were 2 to 3 feet (0.7 to 0.9 m) up to 8 feet (2.4 m) tall in 1946 when planted, are 4 in. (10.2 cm) dbh (diameter breast height) and have basal areas of 0.8 sq. dm. The most invasive species in this planting has been red maple (A. rubum L.).


The following table summarizes chemical treatment. Best control possible results from the following treatments:
1. Stump application of 20% glyphosate in August/September.[29]
2. Wick application of 2 1/2 3% glyphosate in May (Lampa 1983).
3. Mist application of 2.4 kg/ha fosamine (ammonium salt) in September.[45]
4. Frill application of Picloram (ready to use) during the growing season.[28]
5. Basal application of 2,4 D in diesel fuel at 2 4% [46] or 12.5% [29] during the first half of the growing season.

Some special features of herbicide use are as follows:
1. Without a surfactant, glyphosate should not harm non target vegetation or surrounding watersheds when used in anaerobic situations. It will degrade more slowly in anaerobic than aerobic conditions.[47]
2. Effectiveness of fosamine (ammonium salt) may be related to downward translocation of plants preparing for dormancy.[45]
3. Picloram + 2,4 D is soil mobile and probably affects non target vegetation in certain areas.[28]
4. If 2,4 D is carefully applied, there is no known damage to surrounding plants or soil fauna (Nat. Conservancy, Great Brit. 1962). Basal applications must completely encircle the trunk to be effective (Pauly 1983).

The following tables show control efforts used against buckthorn:

Trials using 2,4-D
Reference and species targeted Application Rate Application Method Application Time Geographic Location Results
Sannikov & Tykvina 1971[46], Rhamnus sp. 2-4% ester w/diesel fuel basal painting up to 10 cm basal diameter first half growing season USSR 100%
Pauly 1983, Rhamnus sp. 4% ester w/diesel fuel basal spray ??? WI good control if completely encircles trunk
Pauly 1983, Rhamnus sp. 4% ester w/diesel fuel stump ??? WI control
Rohrig 1953[48], F. alnus 0.2-0.9% ester aqueous foliar, hand sprayed Mar-Aug Germany Poor, defoliated growth reflush
Parsons 1983[49], F. alnus 1--1.5% diesel fuel surfactant foliar, tractor sprayer growth flush OH some control of resprouts following mowing

Trials using AMS
Reference and species targeted Application Rate Application Method Application Time Geographic Location Results
Packard 1983[42] aqueous as concentrated as possible stump painting year-round IL control. Best control on fresh cuts.

Trials using glyphosate
Reference and species targeted Application Rate Application Method Application Time Geographic Location Results
Lampa 1983, F. alnus 2.5-3% wick May-June IL 90-100% control.
Chapman 1983[50], F. alnus 10% mist bottle, stumps less than 5 cm dbh August MI control.
Chapman 1983[50], F. alnus 10% mist bottle, stumps greater than 12 cm dbh August MI resprouting Sept.

Trials using Fosamine
Reference and species targeted Application Rate Application Method Application Time Geographic Location Results
Pauly 1983, Rhamnus sp. 4% mist sprayer, seedlings mid-late summer WI 60-70%. Recommend for fall (Oct) application.
Niehuss, 1974,[45] F. alnus 2.4 kg/ha mist sprayer Sept Great Britain 97.5% control after 1 year.

Trials using Picloram (25%)+2,4-D (75%)
Reference and species targeted Application Rate Application Method Application Time Geographic Location Results
Pauly, 1983, Rhamnus sp. ready to use squirt bottle stump summer WI good control


Combined methods may increase control. Combining cutting with herbicide use may control buckthorn when burning conditions are poor or where burning increases buckthorn invasion. Resprouts resulting from cutting or mowing probably are highly susceptible to translocatable herbicides because of decreased distance to roots, and greater absorption by young shoots. Depletion of root carbohydrates may increase transfer rates of food (and herbicides) to roots.[51]

Biological Control:

R. cathartica is an alternate host for oat rust (Puccina coronata).[23] Because North American insects do not readily feed on buckthorn (probably because of emodin), many host specific European insects of the Rhamnaceae were evaluated for potential Canadian introduction to control buckthorn.[52] Because R. cathartica is agronomically a worse pest, and is of less ornamental value than some other buckthorns, further studies have been limited to R. cathartica pests including Scotosia vetulata Schiff. and Triphos dubiata L..[52] Results are unknown.

An attempt to simulate this decline was initiated in Wisconsin by buckthorn inoculation of Triocothecum roseum, a fungus potentially causing root rot.[27] No results are available.


Management Research Programs:

States where this is being managed and some contacts:

Fran Harty
Illinois Dept. of Conservation
Forestry and Natural Heritage NE Illinois
No. 8 Henson Place
Champaign, IL
217/333 5773

Wayne Lampa
Resource Naturalist Specialist
DuPage Co.
Forest Preserve Dist.
Wheaton, IL
312/790 4900

Steve Packard
The Nature Conservancy
Illinois Field Office
79 West Monroe St., Suite 708
Chicago, IL 60603
312/346 8166

George Ware
Research Director
Morton Arboretum
Lisle, IL 63502
312/968 0074


John Bacone
Director of Division of Natural Preserves
Indiana Dept. of Natural Resources
601 State Office Bldg.
Indianapolis, IN 46204
317/232 4052


Donald R. Farrar
Associate Professor
Department of Botany
Bessey Hall
Ames, IA 50011
515/294 4846


Barb Andreas
216/292 2389


Kim Chapman
Department of Biology
Western Michigan University
Kalamazoo, MI 49008
517/373 1552


Virginia Kline
University of Wisconsin Madison
1207 Seminole Hwy.
Madison, WI 53711
608/263 7344 or 608/262 2179

Wayne Pauly
Dane Co. Naturalist
Dane Co. Hwy. Dept.
2302 Fish Hatchery Rd.
Madison, WI 53713
608/266 5922

Don Reed
Principle Biologist
SE Wisconsin Regional Planning
Box 162
Waukesha, WI
414/547 6721




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Additional References

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  • Bodeux, A. 1957. (The Campine Calluna heaths and conditions for their afforestation.) (French) Repr. from Revue de l'Agricuture 1960 (abstract no. 456).
  • Eglite, A. and Zile, M. 1957. (Destroying trees and shrubs with 2 4 D and 2,4,5 T Na salts.) (Latvian) Latvijas PSR Zinatnu Akademijas Vestis, Riga No. 3. Taken from: Forestry Abstr. 20(2): 246; 1959 (Abstract No. 1958).
  • Forsyth, J.L. 1974. Geologic conditions essential for the perpetuation of Cedar Bog, Champaign County, Ohio. Ohio J. of Sci. 74(2): 116 125.
  • Gleason, H.A.; Crouquist, A. 1963. Manual of vascular plants of northeastern United States and adjacent Canada. New York: Van Nostrand Reinhold Co. 810 p.
  • Harris, S.W.; Marshall, W.H. 1963. Ecology of water level manipulations on a northern marsh. Ecology 44: 331 343.
  • Kohring, Margaret. 1978. Effect of a fall burn on Bakertown Fen, Berrien Co., MI. Located at TNC, The Nature Conservancy, Midwest Regional Office. 21 p.
  • Kornev, V.P. 1952. (Changes occurring in the underwood of Scots Pine stands in the course of rotation.) (Russian) Lesn. Hoz. 5(2): 65 70. Taken from: Forestry Abstr. 16(2): 187; 1955 (Abstract No. 1542).
  • Kral, R. 1981. Some distributional reports of weedy or naturalized foreign species of vascular plants for the southern states, particularly Alabama and middle Tennessee. Castanea 46(4): 334 339.
  • Lovely, D.M. 1981. Wingra Fen vegetation and hydrologic studies. Submitted to Friends of Univ. WI Arboretum, Madison, WI. 24 p.
  • McClain, William. 1983 Nov. 11. Heritage Botanist, IL Dept. of Conservation. Telephone conversation with C.K. Converse, The Nature Conservancy, Midwest Regional Office.
  • Nature Conservancy. London. Toxic chemicals and wildlife section. 1962 1963. Studies on the side effects of arboricides. Extracted from Report. p. 72 73. Taken from: Forestry Abstr. 25(2); 1964 (Abstract no. 2325).
  • Raulo, J.; Leikola, M. 1975. (Studies on the annual height growth of trees.) (Finnish) Metsantutkimuslaitoksen Julkaisuja 81(2): 1 19. From English summary and chart (p. 10).
  • Rosendahl, C.O. 1970. Trees and Shrubs of the Upper Midwest. Minneapolis, MN: Univ. Minnesota Press. 411 p.
  • Sukachev, V.N. 1928. Principles of classification of the spruce communities of European Russia. J. Ecology 16(1): 1 18.
  • Trial, H. Jr.; Dimond, J.B. 1979. Emodin in buckthorn: a feeding deterrent to phytophagous insects. Can. Entomol. 111: 207 212.
  • Ziani, P. 1957. The amelioration by afforestation of strongly podzolized degraded sites of the continental oak region. (Croat.) Sum. List. 81(5/6): 169 205. Taken from: Forestry Abstr. 19(4): 530; 1958 (Abstract No. 4212).

Original Document

Element Stewardship Abstract; Carmen K. Converse, 2007.

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