Ulmus pumila L., Ulmaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  yes

Risk assessment results:  High risk, score: 9 (Go to the risk assessment)

Common name(s): [more details]

Chinese: yu shu

English: Chinese elm, Siberian elm, dwarf elm, littleleaf elm

Habit:  tree

Description:  "Trees, to 25 m tall, d.b.h. to 1 m, deciduous. Bark dark gray, irregularly longitudinally fissured. Branchlets yellowish gray, glabrous or pubescent, unwinged and without a corky layer, with scattered lenticels. Winter buds dark brown to red-brown, ± globose to ovoid; inner bud scale margin usually white ciliate. Petiole 4-10 mm, pubescent; leaf blade elliptic-ovate to elliptic-lanceolate, 2-8 x 1.2-3.5 cm, abaxially pubescent when young but glabrescent or with tufts of hairs in vein axils or sometimes a few hairs on midvein and in forks of secondary veins, adaxially glabrous, base obliquely to symmetrically obtuse to rounded, margin simply or sometimes doubly serrate, apex acute to acuminate; secondary veins 9-16 on each side of midvein. Inflorescences fascicled cymes on second year branchlets, appearing before leaves. Perianth 4-lobed, margin ciliate. Samaras whitish tan, ± orbicular to rarely broadly obovate or elliptical, 1-2 x 1-1.5 cm, glabrous except for pubescence on stigmatic surface; stalk 1-2 mm; perianth persistent. Seed at center of samara or occasionally slightly toward apex but not reaching the apical notch" (Flora of China Online).

Habitat/ecology:  "Grass- and woodland, disturbed sites.  This tree is fast growing and occurs in a wide range of habitats.  Seedlings may form dense thickets with hundreds of plants.  The tree can become dominant in prairies subjected to disturbances and displaces native forbs and grasses"  (Weber, 2003; p. 445).

In China (native), "slopes, valleys, plains; 1000-2500 m.  This species is cultivated throughout China" (Flora of China Online).

Propagation:  "It produces seeds abundantly which are dispersed by wind.  It sprouts vigorously from the roots"  (Weber, 2003; p. 445).

Native range:  China, Korea, Mongolia, eastern Russia; central Asia (Flora of China Online).

Presence:

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 181)
North Korea North Korea	North Korea (Democratic People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea South Korea	South Korea (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (continental except west coast) United States (other states)	USA (Florida)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control:  Control information from the Plant Conservation Alliance's Alien Plant Working Group.

Physical:  "Seedlings can be hand pulled.  Larger trees may be girdled but not too deeply in order to prevent resprouting from the roots.  In fire-adapted communities, regular burning may control this tree"

Chemical:  "Stumps of cut trees can be treated with glyphosate to prevent resprouting"  (Weber, 2003; p. 445).