WHITE POPLAR [Populus alba L.] POAL7 Problem: Native to Eurasia, white poplar (WP) can outcompete native tree and shrub species in open areas by forming clonal stands that can interfere with natural succession.3 Habit: Deciduous tree up to 100 ft. high with widely spreading branches (Fig 1.).1 Reproduction: Wind- dispersed seeds can move Fig. 1 UGA 5273099 long distances, but are not highly viable; PA mostly spreads vegetatively via prolific root suckers.2 Leaves: Simple, alternate, oval with irregularly toothed margins on short shoots to maple-leaf shaped, 3-7 lobed on long shoots (Fig. 2 and 3)3; leaf tip is pointed, and leaf base is truncate or slightly heart-shaped.1 Young leaves are covered in dense white hairs (i.e., tomentose), and older leaves are dark green and hairless above, and covered with the dense white hair on lower leaf surface.3 Stems: Bark is smooth and greenish-white on younger trees, and becomes darker grey and furrowed on older trees (Fig 5).3 Young twigs are densely tomentose and pith of stem is star-shaped (5-pointed) in cross section.3 Flowers: Trees are dioecious (separate male and female trees); flowers are contained in pendulus catkins (~2 inches long) that appear before leaves emerge in spring (Fig. 4).2

Fig. 2 UGA 5242089 Fig. 3 UGA 5386501

TREE WHITE POPLAR Populus alba L.

Fig. 4 UGA 0008132 Fruits/Seeds: Fruits are small (5-7.5 mm), dark brown and dry.2 Cottony white hairs at- tached to the seed allow for wind transport. Seeds mature in late spring to early summer and are usually detatched from tree by late spring.2 Habitat: Areas of disturbance Fig. 5 UGA 5274003 with ample sun such as fields, forest edges and wetland. Tolerates a variety of soils and different levels of pH, as well as a fair amount of salt.2 Similar Species: Similar to bigtooth aspen (Populus gran- didentata Michx.)(BTA), quaking aspen (P. tremuloides Michx.)(QA), and other Populus hybrids, but most of these species have laterally flattened leaf petioles and the leaves are coarsely toothed on BTA (Fig. 6) and finely toothed on QA (Fig. 7).2 WP has rounded leaf petioles and palmately lobed leaves on its longer shoots. WP terminal buds are tomentose, where as the others mentioned above are nearly glabrous to finely hairy.

Fig. 6 UGA 0008293 Fig. 7 UGA 0008295 Populus alba (white poplar) Text Citations: 1. Gleason, H. A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 2nd ed. The New York Botanical Garden, Bronx, NY. 2. Mehrhoff, L. J., J. A. Silander, Jr., S. A. Leicht, E. S. Mosher and N. M. Tabak. 2003. IPANE: Invasive Plant Atlas of New England. Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA.URL: http://www.ipane.org 3. Remaley, T., and J.M. Swearingen. 2005. Plant Conservation Alliance fact sheet: white poplar. http:// www.nps.gov/plants/alien/fact/poal1.htm (accessed February 3, 2010

Photograph Information: Figures 1 and 5 (photographer: Leslie J. Mehrhoff, University of Connecticut) Figure 2 (photographer: Richard Old, XID Services) Figure 3 (photographer: Joseph DiTomaso, University of California- Davis) Figure 4, 6 and 7 (photographer: Paul Wray, Iowa State University Photographs reproduced from www.bugwood.org.