Oriental Lady's Thumb (Invasive Exotic Plants of North Carolina)

Oriental Lady's Thumb

Persicaria longiseta

Summary ⁹

Persicaria longiseta is a species of flowering plant in the knotweed family known by the common names Oriental lady's thumb, bristly lady's thumb, Asiatic smartweed, long-bristled smartweed, Asiatic waterpepper, bristled knotweed, bunchy knotweed, and tufted knotweed. It is native to Southeast Asia, and it is present in North America and Europe as an introduced species and often a weed.

Impacts and control ¹⁰

More info for the terms: fire management, invasive species, natural, nonnative species, prescribed fire

Impacts: As of this writing (2010) there is little published literature documenting the impacts of Oriental lady's thumb. Fact sheets suggest that Oriental lady's thumb has the potential to invade shaded or moist plant communities and displace native species [35,66,69]. The documentation of Oriental lady's thumb plants dominating an open field in Connecticut and a floodplain forest in New Hampshire [35] suggests that displacement of native species is possible. However, in the USDA Forest Service's Eastern Region, Oriental lady's thumb is classified as a widespread nonnative species that is restricted to disturbed areas and is not invasive in undisturbed habitats [65].

Control: As of 2010, little information is available regarding control of Oriental lady's thumb. In all cases where invasive species are targeted for control, no matter what method is employed, the potential for other invasive species to fill their void must be considered [5]. Control of biotic invasions is most effective when it employs a long-term, ecosystem-wide strategy rather than a tactical approach focused on battling individual invaders [33].

Fire: For information on the use of prescribed fire to control this species, see Fire Management Considerations.

Prevention: It is commonly argued that the most cost-efficient and effective method of managing invasive species is to prevent their establishment and spread by maintaining "healthy" natural communities 33,51 and by monitoring several times each year [25]. Managing to maintain the integrity of the native plant community and mitigate the factors enhancing ecosystem invasibility is likely to be more effective than managing solely to control the invader [21].

Weed prevention and control can be incorporated into many types of management plans, including those for logging and site preparation, grazing allotments, recreation management, research projects, road building and maintenance, and fire management [67]. See the Guide to noxious weed prevention practices [67] for specific guidelines in preventing the spread of weed seeds and propagules under different management conditions.

Cultural control: No information is available on this topic.

Physical or mechanical control: A USDA Forest Service fact sheet suggests that Oriental lady's thumb may be controlled by hand pulling, digging up small infestations, or mowing frequently [66].

Biological control: As of this writing (2010) no biological control agent has been identified to control Oriental lady's thumb. A fact sheet from Virginia reports that Oriental lady's thumb has few natural predators [69].

Biological control of invasive species has a long history that indicates many factors must be considered before using biological controls. Refer to these sources: [70,79] and the Weed control methods handbook [63] for background information and important considerations for developing and implementing biological control programs.

Chemical control: A USDA Forest Service fact sheet suggests that Oriental lady's thumb can be controlled using any general-use herbicide, though its occurrence in riparian areas may limit herbicide application [66].

Herbicides are effective in gaining initial control of a new invasion or a severe infestation, but they are rarely a complete or long-term solution to weed management [6]. See the Weed control methods handbook [63] for considerations on the use of herbicides in natural areas and detailed information on specific chemicals.

Integrated management: No information is available on this topic.

Habitat characteristics ¹¹

More info for the terms: mesic, phenotypic plasticity

General Oriental lady's thumb occurs on a variety of sites, including wetlands and riparian or floodplain, bottomland, and upland forests (see Habitat types and plant communities). Floras report Oriental lady's thumb in disturbed areas [12,16,48], including roadsides [34,55], along railroads [39], and in "waste" areas [12,34,57,73]. It also occurs along trails [7,19,35,58] and in fallow fields, hedgerows [55], lawns [38], gardens [34], and old home sites [35].

Elevation: In North America, Oriental lady's thumb occurs from 0 to 1,000 feet (0-300 m) [12].

Climate: Its wide North American distribution both north to south and east to west suggests that Oriental lady's thumb tolerates a range of climates. Annual precipitation for sites with Oriental lady's thumb averaged 42 inches (1,064 mm) in Maryland [54] and 44 inches (1,120 mm) in New Jersey [10].

Soils: Floras report Oriental lady's thumb occurring on moist soil [13,48,73,80], though it is occasionally reported in dry areas [35,73]. In more than 40 terrestrial field records from Connecticut, Massachusetts, and New Hampshire, the majority of sites were described as mesic, a few were described as saturated or inundated, and only 1 was described as dry [35]. In Massachusetts and Connecticut, Oriental lady's thumb was restricted to consistently moist soils that did not flood [58], but other sources report it occurring in areas that flooded or were inundated with water [8,27,35,52]. Some sources state that Oriental lady's thumb occurs on well-drained soils [10,11,46]. In greenhouse experiments, Oriental lady's thumb roots showed high phenotypic plasticity in response to moisture availability; both flooding and lack of moisture led to lower root biomass. Oriental lady's thumb plants produced the longest roots when exposed to constant moisture, and roots were shortest when exposed to dry or flooded conditions [3].

Oriental lady's thumb is often associated with sandy soil, including soils dominated by sand in Massachusetts and Connecticut [58], deep sandy soil in Maryland [52], and coarse sand in Texas [9]. It occurred in silt loams at multiple locations in Pennsylvania [44,46]. In Massachusetts and Connecticut, Oriental lady's thumb occurred on soils with a broad range of macronutrient availabilities and soil pH (range 4.8 to 8) [58].

Sources and Credits

(c) harum.koh, some rights reserved (CC BY-SA), uploaded by harum.koh, https://www.flickr.com/photos/harumkoh/15324278929/
(c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/jroldenettel/20724530279/
(c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/jroldenettel/20901592632/
(c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/jroldenettel/20901565072/
(c) Mattie Altenberger, some rights reserved (CC BY-NC), uploaded by Mattie Altenberger
(c) Gerrit Davidse, some rights reserved (CC BY-NC-SA), http://images.mobot.org/tropicosdetailimages/TropicosImages2/100274000/C291EEA0-4B2A-493E-93C5-192944676D5F.jpg
(c) Kenpei, some rights reserved (CC BY-SA), https://upload.wikimedia.org/wikipedia/commons/1/10/Polygonum_longisetum2.jpg
(c) Dalgial, some rights reserved (CC BY-SA), https://upload.wikimedia.org/wikipedia/commons/0/0f/Polygonum_longisetum_3.JPG
Adapted by Kate Wagner from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Persicaria_longiseta
Public Domain, http://eol.org/data_objects/24629846
Public Domain, http://eol.org/data_objects/24629838

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