Mimosa

Albizia julibrissin

Summary 8

Albizia julibrissin (Persian silk tree, pink silk tree) is a species of tree in the family Fabaceae, native to southwestern and eastern Asia.

Ecological threat in the united states 9

Because silk tree can grow in a variety of soils, produce large seed crops, and resprout when damaged, it is a strong competitor to native trees and shrubs in open areas or forest edges. Dense stands of mimosa severely reduce the sunlight and nutrients available for other plants.

Prevention and control 10

Do not plant silk tree. Trees can be cut at ground level with power or manual saws. Cutting is an initial control measure, best done prior to seed set, and usually requires follow-up cuttings in combination with herbicide treatments due to re-sprouts. Systemic herbicides like glyphosate and triclopyr are effective.

Habitat in the united states 11

Silk tree takes advantage of disturbed areas, often spreading by seed from nearby ornamentals or from contaminated fill dirt. It prefers full sun and is often seen along roadsides and open vacant lots in urban/suburban areas. Silk tree can tolerate partial shade but is seldom found in forests with full canopy cover, or at higher elevations (above 900 m or 3,000 ft), where cold hardiness is a limiting factor. It can, however, become a serious problem along riparian areas, where it becomes established along scoured shores and where its seeds are easily transported in water. Like many successful exotics, it is capable of growing in a wide range of soil conditions.

Fire management considerations 12

More info for the terms: cover, fire management, fire suppression, hardwood, natural, nonnative species, prescribed fire, presence, restoration, top-kill

Available evidence suggests that a single fire will not control mimosa and may promote its establishment.

Potential for postfire establishment and spread: Mimosa is likely to persist by sprouting and, if a seed source is available, establish from seed after fire. Although data regarding mimosa's response to fire are lacking, mimosa is known to sprout following injury or top-kill (see Vegetative regeneration and Control), and evidence suggests that seed germination may be stimulated by heat scarification (see Plant response to fire). Additionally, mimosa seems to grow best on disturbed sites with open canopies (see Successional Status). These traits suggest that burned sites should be monitored for postfire establishment and spread of mimosa if it occurs onsite or nearby.

Preventing postfire establishment and spread: Preventing invasive plants from establishing in weed-free burned areas is the most effective and least costly management method. This may be accomplished through early detection and eradication, careful monitoring and follow-up, and limiting dispersal of invasive plant seed into burned areas. Specific recommendations include:

  • incorporate cost of weed prevention and management into fire rehabilitation plans
  • acquire restoration funding
  • include weed prevention education in fire training
  • minimize soil disturbance and vegetation removal during fire suppression and rehabilitation activities
  • minimize the use of retardants containing nitrogen and phosphorus
  • avoid areas dominated by high priority invasive plants when locating firelines, monitoring camps, staging areas, and helibases
  • clean equipment and vehicles prior to entering burned areas
  • regulate or prevent human and livestock entry into burned areas until desirable site vegetation has recovered sufficiently to resist invasion by undesirable vegetation
  • monitor burned areas and areas of significant disturbance or traffic from management activity
  • detect weeds early and eradicate before vegetative spread and/or seed dispersal
  • eradicate small patches and contain or control large infestations within or adjacent to the burned area
  • reestablish vegetation on bare ground as soon as possible
  • avoid use of fertilizers in postfire rehabilitation and restoration
  • use only certified weed-free seed mixes when revegetation is necessary

For more detailed information on these topics see the following publications: [5,16,43,118]. Use of prescribed fire as a control agent: No information was available (as of 2010) on the use of prescribed fire to control mimosa. Given its persistence after fires (see Plant response to fire and FIRE REGIMES), fire alone is not likely to control mimosa. MANAGEMENT CONSIDERATIONS SPECIES: Albizia julibrissin

IMPORTANCE TO LIVESTOCK AND WILDLIFE:
Mimosa may be a minor food source for some wildlife and has some potential as livestock feed.

Palatability and/or nutritional value: Mimosa seed may provide some food for birds and squirrels [54,123], while butterflies and hummingbirds likely consume mimosa nectar [54,61]. Mimosa leaves may provide browse for deer and other wildlife [1,54,98]. According to Kartesz [61], mimosa has been reported as toxic.

Mimosa's nutritional value and growth rate give it potential as a summer browse species for livestock in the southeastern United States [17,99]. In a test of mimosa as a forage species in the Louisiana coastal plain, mimosa had consistently high leaf crude protein level [99]. In an analysis of mimosa as forage in Arkansas, nitrogen levels met the nutritional requirements of cattle and domestic goats, and the presence of secondary metabolites were below detectable levels [17]. In a study of mimosa's potential as domestic goat feed, digestibility and chemical composition were similar to alfalfa (Medicago sativa) [12]. In a domestic sheep feeding trial, mimosa digestibility was 61%, and there were no signs of toxicity [13]. In an experiment on mimosa as domestic goat forage, herbage mass production was adequate [1]. Other experiments suggest that mimosa tolerates 2 complete defoliations during the grazing season [3] and that yield was maximized when 6 to 8 weeks of regrowth occurred between harvests [13,14]. Despite mimosa's tolerance, requirements for managing defoliation are likely greater than required of currently used forage species [99]. Although domestic goats [3] and domestic sheep [3,13] eat mimosa, it has been shown to have relatively low palatability compared to some available foods [1,3]. Mimosa's other limitations include its potential to become invasive [99] (see Impacts) and a lack of evidence, as of 2010, that it significantly improves animal performance measures such as weight gain [3].

Cover value: Wick and Walters (1974 cited in [98]) state that mimosa provides valuable cover for wildlife. OTHER USES:
Ornamental: As of 2009, Mimosa was a popular ornamental throughout its US range [23,25,30,41,104,120], including Ohio [15], Connecticut [19], Florida [40], Texas [26,123], and Utah [128]. Around 2005, 75% of nurseries in the Tidewater area of Virginia carried mimosa [28]. Information on mimosa seed collection, nursery practice, and planting is provided by Parrotta and others [98] and Williams and Hanks [129].

Rehabilitation planting: Mimosa has been recommended as a soil builder [100] and is used in rehabilitation planting on landfills [63,105] and mine sites [11,100].

Other: Mimosa may be used for timber [61,123] and as an alleycrop species and mulch in legume production [60,79]. Although mentioned as a timber plant by Kartesz [61] and apparently used in cabinetmaking in Asia [123], mimosa's weak and brittle wood was noted in a review [9]. There have been some successes with experimental trials that used mimosa as an alleycrop species to maintain or improve soil fertility while growing commercial crops. Mimosa fixed an estimated 245 pounds of nitrogen/acre over one growing season in an experimental planting in Alabama [13]. However, its use on broad scales is not recommended [60,79]. Kartesz [61] notes that mimosa is edible and useful in erosion control. Use as a biofuel [83] has also been reported. IMPACTS AND CONTROL:
Impacts: Several assertions have been made regarding mimosa ability to invade native plant communities [26], displace natives [82,111], and prevent regeneration of natives [82,126]. According to Weber [126] and Demers and Long [25], dense mimosa stands reduce light levels and available nutrients, which reduces establishment of native species [126]. However, a 2005 review notes that the potential impacts of mimosa establishment and spread are unknown [23].

Despite a lack of data on the impacts of mimosa on native habitats, mimosa is commonly considered a weed of concern in the south-central and southeastern United States. Miller [82] states that mimosa is 1 of the 16 most prevalent nonnative species in subtropical forests of the southeastern United States. Managers in Alabama, Arkansas, and Kentucky consider mimosa a problem weed [76]. In Texas mimosa is widespread and "can aggressively invade native habitats" [26]. According to a 2008 review [96], mimosa is listed as invasive in 8 southern and mid-Atlantic states. Mimosa was 1 of 12 species commonly reported as a problem by federal, state, and nongovernmental land managers of the southern Appalachians [66]. In the mid-1970s, the small size, scattered spatial arrangement, and occurrence of mimosa populations only on disturbed sites in Great Smoky Mountains National Park led to the conclusion that mimosa had very little impact on native flora of that area, despite occurrence in riparian plant communities [8]. From 1994 to 2005, mimosa was one of the 9 most common weeds in the Great Smoky Mountains National Park [127]. However, the impact of mimosa establishment in this area had not been determined as of 2008. Mimosa is classified as a weed that easily spreads into native communities and displaces native species in several southeastern states including Tennessee [106], Georgia [37], and Florida [35]. It frequently occurs in the central peninsula and northern regions of Florida [131]. In 2005, mimosa was classified as a "significant threat" instead of a "severe threat" in Kentucky due to fewer impacts on native plant communities and fewer invasive characteristics than weeds that pose more severe threats [62]. As of 2003, mimosa was considered "moderately invasive" in Virginia due to slow spread and negligible impact on ecosystem processes [124]. It had low management priority in another Virginia study area due to comparative ease of control [28].

Riparian habitats may be at greater risk of mimosa invasion than other communities, likely due to regularly disturbed soils in riparian areas as well as the potential for mimosa seeds to disperse in water [9]. Mimosa is reportedly a "serious problem" along some streams in Tennessee [9], where it has been documented in cobble bars of the New River [6] and streambanks in Great Smoky Mountains National Park [8]. A review of southeastern weeds notes that mimosa invades riparian habitats, spreads along stream networks, and can reduce native species and hardwood regeneration in riparian habitats [82]. Mimosa was described as a "common pest" of the floodplain in Rock Creek Park in Washington DC [33]. It was reported on an island in the Potomac River, Maryland, that had experienced little human disturbance but had greater light penetration than mainland forests, likely due to higher velocities of previous floods on the island compared to the mainland [102]. Mimosa has also been reported in riverbank communities in subtropical forests within its native range [65].

Control: Prevention has been recommended to minimize further spread of mimosa, while control of established populations is generally accomplished with some combination of mechanical and chemical treatments.

Fire: The ability of prescribed fire to control mimosa is likely limited and is discussed in Fire Management Considerations.

Prevention: Reducing seed sources and disturbances have been suggested to help prevent the spread of mimosa. The Southern Region of the US Forest Service prohibits planting mimosa on National Forest lands [117]. Using natives instead of mimosa for ornamental planting has been recommend [28,111], and Swearingen and others [111] provide a list of alternate native species for planting. For an example of selecting and implementing a weed risk assessment, see Jefferson and others [58]. In Great Smoky Mountains National Park, reducing anthropogenic disturbance was suggested to limit mimosa establishment [8].

Cultural: No information is available on this topic.

Physical and/or mechanical: Effective mechanical treatments typically involve repeated girdling or cutting of mimosa close to the ground before seed production. Repeated cutting or cutting in combination with herbicide application is necessary to control sprouting [9,111,126]. For example, in experimental plots in North Carolina mimosa coppiced in February grew to an average height of 54 inches (137.7 cm) by the end of June. A cutting height of 10 inches (25 cm) significantly (P=0.013) decreased herbage mass production compared to a cutting height of 20 inches (50 cm) [1]. Results of another experiment suggest that mimosas cut to 4 inches (10 cm) 2 or 3 times per growing season had shorter life spans than those cut at 20 inches (50 cm) or higher. Despite the difference, mimosas cut to 4 inches survived an average of 641 days [99]. Swearingen and others [111] recommend cutting mimosa at ground level. Several reviews [9,111,126] recommend cutting before seed production to prevent seed dispersal.

Seedlings up to 4 inches (10 cm) have been controlled by regular mowing [8], and seedlings up to 10 inches (25 cm) can be pulled by hand [25]. Effective hand-pulling of mimosa requires removal of the entire root [9,126].

Biological: Research into appropriate biological control agents was lacking as of 2008. A root fungus [9], a bruchid beetle (Bruchidae) [24,89], and a psyllid [120] apparently impact mimosa to some extent, but there were no data on their potential as biological control agents.

Mimosa is susceptible to a Fusarium root fungus, which causes vascular wilting and typically results in rapid mortality [9,30,40,96,123]. Mimosa strains that are resistant to the fungus are available [74,116]. The use of this root fungus to control mimosa could be limited, depending on the extent to which these strains have established in native plant communities.

Bruchid beetles infested 21% of mimosa seeds in a germination study [89], and DeLoach [24] suggests bruchid beetles may be a useful biological control for mimosa.

The introduced psyllid Acizzia jamatonica is apparently an obligate feeder of Albizia and was documented in Clarke County, Georgia, in 2006 [120].

Chemical: Herbicides are often used to control mimosa sprouting following mechanical treatments [25], or as a basal bark application on larger trees. Trees larger than 3 inches (1.2 cm) in diameter may require retreatment [71]. Recommended herbicides and applications for mimosa saplings and large trees are described in several reviews [9,25,71,83,126]. See the Weed control methods handbook for considerations on the use of herbicides in natural areas and detailed information on specific chemicals. Integrated management: Information on integrated management of woody eastern weeds is reviewed by Webster and others [127]. Miller [82] recommends integrated control for several southeastern weeds, including mimosa. It is apparently common to combine mechanical and chemical treatments to control existing mimosa trees and prevent sprouting [9,111,126]. Used in conjunction with preventative measures, this would reduce the risk of mimosa spreading into new sites [8,111,117].

Sources and Credits

  1. (c) Alexxx Malev, some rights reserved (CC BY-SA), https://www.flickr.com/photos/alexxx-malev/11241581463/
  2. (c) Martin LaBar, some rights reserved (CC BY-NC), http://www.flickr.com/photos/32454422@N00/3824018
  3. (c) matthew_salkiewicz, some rights reserved (CC BY-NC), uploaded by Matthew Salkiewicz, http://www.inaturalist.org/photos/392907
  4. (c) rachelgreenbelt, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/rachelgreenbelt/15319854856/
  5. (c) rachelgreenbelt, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/rachelgreenbelt/15336797715/
  6. (c) Linda Jo, some rights reserved (CC BY-NC), uploaded by Linda Jo Conn, http://www.inaturalist.org/photos/887260
  7. (c) Sam Kieschnick, some rights reserved (CC BY-NC), http://www.inaturalist.org/photos/578392
  8. Adapted by Kate Wagner from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Albizia_julibrissin
  9. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22948491
  10. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22733954
  11. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22948493
  12. Public Domain, http://eol.org/data_objects/24634049

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