Populus deltoides Marshall

Cottonwood

Broad-crowned tree about 30 m tall. Bark grey and fissured. Buds brown, hairless and sticky shiny-resinous. Shoots glabrous, sometimes strongly angled to almost winged, generally yellowish brown. Leaves triangular to broadly ovate, 7-12 cm long, coarsely serrated with incurved teeth, persistently ciliate, base of leaf near petiole with, mostly, 2-3 glands. Leaf stalk flattened sideways, often reddish. Catkins 7-10 cm long. Fruit capsules 3-4 valved.

North America

The complex taxonomy of this species was revised by Eckenwalder (1977).

Of those available in Australia the most prevalent are the subsp. monilifera (W. Ait.) Eckenw. [P. monilifera Aiton, P. deltoides var. monilifera (Aiton) A. Henry] and subsp. deltoides [P. virginiana Foug., P. angulata Ait., P. angulata var. missouriensis A. Henry].

The taxonomic recognition of taxa according to leaf shape and size, margin toothing and ciliation, and the presence or absence of angled stems does not seem profitable for SE Australia as many transitional forms may be found. The situation is confused by the apparent existence of a range of horticultural clones that show slightly different characters. Trees under the old name P. angulata have been grown in plantations for the production of matches.

Distinguished by the persistently ciliate translucent leaf margins always with 2-3 glands at the base of the often large blade; cf. P. ×canadensis.

NSW: Goulburn (Belmore Park); Jenolan Caves; Sydney (Royal Botanic Garden Sydney); Wagga Wagga (Victory Memorial Gardens); Wellington (Park). ACT: Acton House. VIC: Terang; Ballarat (Ballarat Botanical Gardens) TAS: Hobart (Royal Tasmanian Botanical Gardens)

Trees with angled shoots: VIC: Cobram & Yarrawonga (Brymay Match Plantation); Richmond (Gosh's Paddock); Melbourne (Royal Botanic Gardens Victoria (Melbourne Gardens) just outside Observatory House).

Source: Spencer, R. (1997). Salicaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.

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Distribution map

Populus deltoides 'Kawa'

A hybrid raised at Palmerston North, New Zealand in 1978. All plants are female. (P. deltoides × P. yunnanensis)

In New Zealand it has been used for woodlot planting and erosion control but may be susceptible to rust infection.

Populus deltoides 'Tasman'

Semi-evergreen. It has a basically upright habit like the Lombardy Poplar but is more open.

Imported from New Zealand (where it is used as a windbreak and said to be rust-resistant) and released in Australia in 1986.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Rosanae
order      Malpighiales
family       Salicaceae
genus        Populus L.