Native Woody of the Southern United through natural geographical expan- sion, sheer aggressive growth in States with Weedy or Invasive Tendencies: A native locations, or anthropogenic activity, can sometimes be chall- Review of Common Offenders enging to keep in-bounds, both in cultivation and in natural ranges. 1 Although not an exhaustive list, Michael A. Schnelle a few that warrant closer monitoring in the southern United

ADDITIONAL INDEX WORDS. anthropogenic disturbance, indigenous plants, States and other regions of the coun- naturalized, nursery crops try are presented.

SUMMARY. Five woody species, black locust (Robinia pseudoacacia), yaupon holly Black locust Ilex vomitoria Prunus serotina carolinus ( ), black cherry ( ), snailvine [ The black locust is a 40- to 60-ft · (formerly carolinum or Epibaterium carolinum)], and southern waxmyrtle [Morella cerifera (formerly Myrica cerifera)], are all native to Oklahoma 35-fttreethatisnativetoforest and nearby states. They all have varying levels of use in and importance to the edges and slopes in the Southern United States nursery industry. Past natural habitats and where these plants have Appalachian and Ozark mountains spread to date, either intentionally or naturally, are discussed here. These native of the United States (disjunct pop- plants have migrated to or have become increasingly dominant in regions of the ulations). At one time, this species continental United States because of prolific fruit loads dispersed by birds and wasreportedin12states,butitis mammals, anthropogenic disturbances, overgrazing pastures, and certain species’ now found throughout the conti- tolerance of environmental extremes. Potential control measures include chemical nental United States. Black locust applications, timely cultivation, heightened awareness of grazing practices, and has displaced other native species prescribed burning. in the northeast, mid-Atlantic, and midwest regions of the Uni- n most settings, native germ- founded on hard science; instead, ted States, as well as California plasm proves, in the worst-case they reflect a set of value judgements (Brusati, 2005; U.S. Department Iscenario, to be ‘‘weedy’’ and, oc- about the timescales of environmen- of Agriculture, 2007). It was in- casionally, invasive. A weed is nor- tal changes and forms of human im- tentionally introduced outside its mally defined as a , native or pact regarded as acceptable within the range, both in the United States non-native, that is not valued where landscape (Kendle and Rose, 2000). and abroad, because of its ability it is growing (U.S. Department of Often when a native species is deemed to mitigate soil erosion and its Agriculture, 2018). In the context invasive, the invasion is associated with usefulness for land reclamation of this review, an ‘‘invasive’’ species anthropogenic disturbance (Simberloff from mining. Black locust is now is defined as a species that not only et al., 2012). Changes in climatic con- growing throughout most of the spreads geographically outside its typ- ditions that have transpired over recent United States. The success of this ical range but also has a proclivity for decades have resulted in altered popu- tree outside of its native range is displacing native flora and fauna. lation dynamics of native species and, attributable to its high photosyn- Reichard and White (2001) defined thus, their geographic ranges (Walther thetic rate, dispersal by birds an invasive species as one that has et al., 2009). and mammals, fast seed germina- spread or is likely to spread into native It is possible that native plant tion, rapid seedling growth, exten- flora and managed plant systems, de- invasions have been underreported. sive root system, tolerance of low velop self-sustaining populations, and In fact, they can be significant and fertility, high genetic variability, become disruptive and/or dominant independent of local land-use and resistance to drought stress, in such systems. The definitions of changes, and they can be influenced air pollutants, temperature ex- native status and alien status are not by the global climate. It is estimated tremes, and most fungal decay that 10% to 20% of all invasive plant (Hanover, 1990; Sabo, 2000). Be- species in North America are native cause black locust quickly shades Received for publication 27 Feb. 2019. Accepted for publication 12 Apr. 2019. to the United States (Nackley et al., sun-loving plants, it invades dis- Published online 7 August 2019. 2017). The debate regarding native turbed habitats, degraded woods, vs. non-native and weedy vs. invasive and thickets, consequently over- 1Department of Horticulture and Landscape Archi- tecture, Oklahoma State University, 358 Agriculture is beyond the intended scope of this whelming native species of prairies, Hall, Stillwater, OK 74078 work, but it has been summarized by oak savannas, and upland forests, This paper was part of the Invasive Plants Research Kendle and Rose (2000). The objec- where it ultimately forms a monocul- Professional Interest Group workshops ‘‘Strategies for tive of this work was to illuminate ture (California Invasive Plant Coun- Mitigating Invasiveness of Native Species,’’ held on 30 Sept. 2017, in Waikoloa, HI, and ‘‘It’s Native. Wait! species important to the ornamentals cil, 2006; Nix, 2017). Suckering It’s Exotic...Oh No, It’s a Nuisance!’’ held on 3 Aug. industry and end-consumers that, results in dense clones that create 2018, in Washington, DC. M.A.S. is the corresponding author. E-mail: mike.sch- [email protected]. Units This is an open access article distributed under the CC To convert U.S. to SI, To convert SI to U.S., BY-NC-ND license (https://creativecommons.org/ licenses/by-nc-nd/4.0/). multiply by U.S. unit SI unit multiply by https://doi.org/10.21273/HORTTECH04334-19 0.3048 ft m 3.2808

• October 2019 29(5) 567 WORKSHOP shaded islands with little ground invasive, under certain conditions spoil. Black cherry is primarily car- vegetation. The lack of ground fuel andwithindefinedgeographic ried by specialty growers and/or can render the use of fire futile in boundaries (Linex, 2014). Although those specifically touting natives of natural disturbance regimes (Wieseler, native to the North Carolina Coastal the United States. It is sometimes 2009). Control measures have in- Plain, it has escaped to the Sandhills regarded as weedy to marginally in- cluded bulldozing and scraping the and Piedmont regions (North Caro- vasive in the United States, and it is soil surface, prescribed burns, and lina Native Plant Society, 2017). East became decisively invasive in Europe annual haying, which may prove viable Texaslandownersperceivethisplantto soon after its introduction. It has for eradicating vulnerable first-year be an invasive species (Vorderbruggen, been introduced or spread to other seedlings. Others have combined me- 2008). Dense, monotypic stands in states, with Minnesota deeming it chanical control with herbicides. forest understories have inhibited in- noxious and prohibiting its sale (In- When black locust is near desirable digenous herbaceous and tree vasive Plant Atlas of the United vegetation, phytotoxicity can occur as regeneration. This, in turn, has led to States, 2018a; Uva et al., 1997). a result of aerial applications or runoff less biodiversity and enhanced fuel Black cherry can grow in a number injury with herbicides such as triclo- loads (Oswald et al., 2017). Limita- of environmental extremes, with the pyr. Glyphosate has also been used tions such as salt intolerance (Paudel exception of chronically wet soils. with varying success. Prescribed burn- and Battaglia, 2015) will likely halt any Given the heavy fruit load annually ing, cutting, or pulling plants often further encroachment, particularly as it dispersed by birds and mammals, it result in increased suckering and pertains to coastal regions, although has naturally spread and/or has been vigorous re-sprouting (Missouri the species does inhabit these areas in intentionally introduced throughout Department of Conservation, 2013). limited populations. the United States, well beyond its Biological control has been contem- Researchers found that pre- aforementioned native range. Natu- plated and/or attempted (Sabo, scribed burning reduced the canopy rally occurring botanical varieties ex- 2000); however, to date, there of yaupon holly but failed to cause ist within the United States, but all is no USDA-approved biocontrol mortality. However, when diesel or share a propensity toward heavy fruit agent (DiTomaso and Kyser, 2013; diesel combined with triclopyr herbi- set, thus contributing to weediness in Wieseler, 2009). Although many cul- cide was applied 6 and 18 months their native range or encroachment in tivars and selections exist for this spe- after burning, a mortality rate as high areas not originally in the species’ cies, Lace Lady and Frisia seed heavily, as 92% was achieved (Mitchell et al., native habitat. with the exception of Pyramidalis, 2005). Yaupon holly is dioecious with Purple Robe, and possibly others that some of the dwarf selections, such as Snailvine are less reproductive. Even if sterility ‘Nana’ and ‘Bordeaux’, that are es- Native to the midwestern and were achieved, and if the resulting sentially sterile/fruitless. Selecting southeastern United States, snailvine selections were aggressively marketed, male cultivars to mitigate weediness is valued for its shiny, green, heart- such plants would still likely sucker, be would likely be futile because of shaped deciduous to semi-evergreen resistant to herbicides, and thrive in the widespread populations of the foliage, brilliant red fruits, and ability a number of environmental extremes. species, and it would be counterpro- to quickly cover unsightly areas or Although the species is ornamental ductive because of the highly sought- trellises in landscape settings. This and has value for erosion control, land after showy fruits borne from female grows from 6 to 12 ft in length, reclamation, and other uses, it should plants, which are its greatest selling and it is commercially available; how- be sold and planted with forethought. point. ever, it is normally offered by specialty Massachusetts and Minnesota, respec- growers as a niche or novelty orna- tively, have ordered sales bans and Black cherry mental due to its reputation for ram- deemed it noxious (Minnesota Black cherry is native to the pant growth and its status of being Department of Natural Resources, eastern United States (Coastal Plains challenging to ‘‘tame’’ (Stump, 2013; 2019). Plants Wiki, 2007), but it can be Vogelpohl, 2014). Snailvine often found as far west as Oklahoma and dominates the ‘‘landscape’’ in both Yaupon holly Texas in canyons, valleys, and rich its native range and beyond due to Yaupon holly is a small tree to bottomlands. It is an attractive 50- its highly reproductive nature via large shrub that can grow from 20 to ft-tall · 30-ft-wide tree with glossy and root sprouts, even with 30 ft in height and 10 to 15 ft in foliage, showy white fragrant spring attempts to eradicate this spe- width. This species is a highly sought- flowers, and beautiful but messy red/ cies (Smith-Rodgers, 2009). This ag- after native woody ornamental due to blue drupes in copious amounts in gressive colonizer (Native Plant its ease of culture and showy charac- late summer to fall. Its fall color can Information Network, 2008) is very teristics, particularly its glossy foliage be striking, with hues of yellow, or- drought-tolerant and can tolerate a and showy red berries on female ange, red, and purple. With its hard, broad spectrum of light exposure, mak- plants. The native range of yaupon reddish-brown wood, black cherry is ing it competitive, if not dominant holly is from Virginia to Florida and commercially significant in the furni- (Rector, 2013). Although mechanical from Oklahoma to Texas along the ture industry, and it is used for pan- control measures work, they are often coastal plains and maritime forests eling, handles, and toys (National temporary due to sprouting from (southeastern United States). How- Museum of American Illustration, roots and stubs. Chemical control, ever, despite its indigenous status, 2018). Additionally, it has been use- although often tenuous due to the it has proven to be weedy, if not ful for reclamation of surface mine sheer tenacity of this native species,

568 • October 2019 29(5) has been accomplished via glyphosate been controlled with triclopyr- nitrogen eutrophication, increased ur- (with repeat applications necessary). picloram mixtures (Shiver et al., banization, and other changes in land Because snailvine often grows over 1991). Various tests of burning, use(Davisetal.,2011). desirable vegetation, it is challenging chopping, and blading methods for to kill unwanted vegetation without this species indicated that it can re- Literature cited causing phytotoxicity to desirable spe- establish itself to pretreatment levels cies in the vicinity (National Plant within 3 years (Van Deelen, 1991). Brusati, E. 2005. Robinia pseudoacacia.4 Information Network, 2008). The Jan. 2019. counterproductive because the red Because of the exponential in- assessment-form/ . fruits are the main impetus for grow- crease in atmospheric carbon dioxide California Invasive Plant Council. 2006. ing this native vine. Rather, careful (CO2) concentrations and the result- California invasive plant inventory. Cal- siting and monitoring of this species ing impacts on climate, it is more likely IPC Publ. 2006-02. California Invasive would be prudent. that both endemic and alien plants will Plant Council, Berkeley, CA. drastically alter ranges, resulting in the Southern waxmyrtle Coastal Plains Plants Wiki. 2007. Prunus expansion of species in some situations serotina. 16 Dec. 2018. . and Watson, 2014) that is valued for et al., 2017). Many invasive events its evergreen foliage, showy blue fruits, are a result of anthropogenic distur- Coder, K.D. 2016. Invasive trees of and overall pleasing growth habit. The bance; therefore, the onus is on scien- Georgia. Univ. Georgia Publ. No. 39. original range for southern waxmyrtle tists, growers, and consumers to keep Davis, M., M.K. Chew, R.J. Hobbs, A.E. was the southeastern United States a watchful eye on land stewardship and Lugo, J.J. Ewel, G.J. Vermeij, J.H. Brown, from New Jersey to Florida and west- other factors that could influence a spe- M.L. Rosenzweig, M.R. Gardener, S.P. ward to Texas (Williamson, 2015); cies’ performance relative to other Carroll, K. Thompson, S.T.A. Pickett, J.C. however, the species is now colonizing plants in the same biological commu- Stromberg, P.D. Tredici, K.N. Suding, other areas of the country or behaving nity. The native species, like intro- J.G. Ehrenfeld, J.P. Grime, J. Mascaro, and aggressively in its native range and is duced plant materials, should be J.C. Briggs. 2011. Don’t judge species on sometimes deemed invasive (Coder, judged on a case-by-case basis. Marble their origins. Nature 474(7350):153–154. 2016; Invasive Plant Atlas of the (2018) suggested that plant selection DiTomaso, J.M. and G.B. Kyser. 2013. United States, 2018b). The species is for a landscape should be predicated Weed control in natural areas in the opportunistic and will quickly domi- on environmental benefits, aesthetic western United States. Weed Res. Info. nate disturbed areas such as clear cuts value, and long-term maintenance Ctr., Univ. California, Davis. and oil fields (Keener et al., 2019). needs/issues, including the potential Gilman, E.F. and D.G. Watson. 2014. Shiflett et al. (2017) described south- for unwanted spread regardless of the Myrica cerifera: Southern waxmyrtle. ern waxmyrtle’s ability to efficiently origin of the species. Univ. Florida, Inst. Food Agr. Sci., IFAS capture light and utilize internal water Few native species are aggressive Publ. ENH-569. movement. These factors promote enough to warrant production and rapid thicket formation while simulta- sales bans in the southern United Hanover, J.W. 1990. Physiological ge- netics of black locust (Robinia pseuodoa- neously discouraging colonization and States; however, they should be mon- cacia L.): A model multipurpose tree expansion of co-occurring species. itored. Regarding potentially prob- species, p. 175–183. Proc. Conf. on Fast Furthermore, this dense growth poses lematic native species, Davis et al. Growing and Nitrogen Fixing Trees, a fire hazard. Paudel and Battaglia (2011) remarked that conservationists Univ. Marburg, West. Germany, 8–12 (2015) hypothesized that southern and land managers should organize Oct. 1989. waxmyrtle had restricted distributions priorities based on whether species near coastal areas, largely due to tidal are producing benefits or harm to Invasive Plant Atlas of the United States. 2018a. Black cherry. 14 Jan. 2019. flooding and higher salinity. However, biodiversity, human health, ecological . areas and is somewhat tolerant of salt sures should range from total eradica- spray (North Carolina State Exten- tion to toleration of the ‘‘new’’ species Invasive Plant Atlas of the United States. sion, 2018). Southern waxmyrtle is as enriching local biodiversity and 2018b. Southern waxmyrtle. 14 Jan. 2019. < adapted to full sun to shade, is pH- facilitating ecosystem restoration as https://www.invasiveplantatlas.org/ 5 > insensitive, tolerates wet to dry and native communities re-assemble and subject.html?sub 6051 . even saline soils, and fixes nitrogen. go forward under a new climate re- Keener, B.R., A.R. Diamond, L.J. Because it can thrive in poor soils, it is gime (Walther et al., 2009). Most Davenport, P.G. Davison, S.L. Ginz- highly adaptable and outcompetes genera are opportunistic, and it is barg, C.J. Hansen, C.S. Major, D.D. other plant materials within or outside noteworthy to observe that native in- Spaulding, J.K. Triplett, and M. Woods. its native range in the United States. vasions are not unique to the United 2019. Alabama plant atlas: Morella cer- No cultivars to date have proven to be States; they occur worldwide (Nackley ifera. 24 Feb. 2019. useful alternatives for reducing its pro- et al., 2017). Current management edu/Plant.aspx?id 2685 . pensity to spread and grow aggres- approaches must acknowledge that Kendle, A.D. and J.E. Rose. 2000. The sively under certain conditions. Up natural systems of the past are chang- aliens have landed! What are the justifica- to 70% of southern waxmyrtle has ing forever due to climate change, tions for ‘native only’ policies in landscape

• October 2019 29(5) 569 WORKSHOP plantings? Landsc. Urban Plan. 47(1):19– Oswald, B.P., M.J. Beierle, K.W. Farrish, U.S. Department of Agriculture. 2007. 31. H.M. Williams, and I. Hung. 2017. Bio- Release brochure for Steiner Group black mass estimations of invasives yaupon, locust (Robinia pseudoacacia). U.S. Dept. Linex, R. 2014. Can a native plant chinese privet and chinese tallow in east Agr., Natural Resources Conservation be noxious or invasive? 6 July 2018. < Texas hardwood and pine ecosystems. Serv., Norman A. Berg Natl. Plant Mate- https://npsot.org/wp/story/2014/ For. Res. 6(2):1–9. 6872/>. rials Ctr., Beltsville, MD. Paudel, S. and L.L. Battaglia. 2015. The U.S. Department of Agriculture. 2018. Marble, S.C. 2018. Native weedy pests of role of light, soil and human factors on the the Deep South. HortScience 53:1244– National Invasive Species Information probability of occurrence of an invasive < 1249. Center (NISIC). 11 Nov. 2018. https:// and three native plant species in coastal www.invasivespeciesinfo.gov/index. Minnesota Department of Natural Re- transitions of coastal Mississippi, USA. J. shtml/>. sources. 2019. Black locust (Robinia pseu- Plant Ecol. 8(5):491–500. doacacia < Uva, R.H., J.C. Neal, and J.M. DiTomaso. ). 25 Jan. 2019. https://www. Rector, B.S. 2013. Invasive vine. 9 Jan. dnr.state.mn.us/invasives/terestrialplants/ < 1997. Weeds of the Northeast. Cornell > 2019. https://ask.extension.org/ Univ. Press, Ithaca, NY. woody/blacklocust.html . questions/127077>. Missouri Department of Conservation. Van Deelen, T.R. 1991. Fire effects in- Reichard, S.H. and P. White. 2001. formation system: Morella cerifera.25 2013. Black locust control. 5 Jan. 2019. Horticulture as a pathway of invasive plant < Nov. 2018. . html#FIRE%20EFFECTS>. Sabo, A.E. 2000. Robinia pseudoacacia Vogelpohl, S. 2014. Know your natives - Mitchell, R.B., J.C. Cathey, B. Dabbert, invasions and control in North America R. Sosebee, and D.F. Prochaska. 2005. and Europe. Student On-line J. 6(3):1–9. Carolina moonseed. 13 Dec. 2018. Managing yaupon with fire and herbicides . ARS/UNL Faculty 201. Young. 2017. Functional traits of expand- ing thicket-forming : Contrasting Vorderbruggen, M. 2008. Foraging Nackley, L.L., A.G. West, A.L. Skowno, < strategies between exotic and native species. Texas. 6 July 2018. http://www. and W.J. Bond. 2017. The nebulous Ecosphere 8(9):1–15 (article e01918). foragingtexas.com/2008/08/yaupon- ecology of native invasions. Trends Ecol. holly.html>. Evol. 32(11):814–824. Shiver, B.D., S.A. Knowe, M.B. Edwards, and W.N. Kline. 1991. Comparison of Walther, G.-R., A. Roques, P.E. Hulmes, National Museum of American Illustration. M.T. Sykes, P. Pysek, I. Kuhn, M. Zobel, Prunus serotina herbicide treatments for controlling com- 2018. Black cherry ( ). 10 S. Bacher, Z. Botta-Dukat, H. Bugmann, < mon coastal plain flatwoods species. South. July 2018. https://americanillustration. B. Czucz, J. Dauber, T. Hickler, V. Jar- > J. Appl. For. 15(4):187–193. org/project/prunus-serotina/ . osik, M. Kenis, S. Klotz, D. Minchin, M. Simberloff, D., L. Souza, M.A. Nunez, Native Plant Information Network. 2008. Moora, W. Nentwig, J. Ott, V.E. Panov, M.N. Barrios-Garcia, and W. Bunn. 2012. . 3 Dec. 2018. . K. Vohland, and J. Settele. 2009. Alien 607. species in a warmer world: Risks and op- Nix, S. 2017. Seven common invasive tree Smith-Rodgers, S. 2009. Window on portunities. Trends Ecol. Evol. species in North America. 12 Nov. 2018. a Texas wildscape: Obnoxious . 9 24(12):686–693. . < vines.html>. 2019. https://www.invasive.org/ alien/fact/rops1.html>. North Carolina Native Plant Society. Stump, B. 2013. Living lightly in Wil- 2017. Ilex vomitoria. 1 Nov. 2018. . < livinglightlyinwilliamsoncounty.blogspot. Jan. 2019. https:/hgic.clemson.edu/ > North Carolina State Extension. 2018. com/2013/05/driven-to-distraction-by- factsheet/waxmyrtle/ . Myrica cerifera. 5 Jan. 2019. . plants.ces.ncsu.edu/plants/all/myrica- cerifera/>.

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