Scientific Name
Populus x acuminata
The prevailing botanic opinion is that the lanceleaf cottonwood tree is a hybrid between the plains cottonwood (Populus sargentii) and the narrowleaf cottonwood (Populus angustifolia), both of which are native to our region. The narrowleaf cottonwood is mostly a tree of the foothills and mountains, but they overlap along the Front Range, allowing for numerous crosses to arise that are consistently intermediate in terms of form, height, girth, bark and leaf shape. As is the case with other cottonwoods, the pith (spongy inner material) of the twigs is star-shaped in cross section, which can be checked since there are often discarded twigs lying on the ground beneath the trees. The leaves have spear shaped tips and can be as broad as they are long, but in general are not as wide as the leaves of plains cottonwood and thus give the tree a finer texture when the tree is leafed out. The leaf stems are like the narrowleaf cottonwood — short and round, so they move in the breeze less than the plains species or the aspen. Lanceleaf cottonwoods grow to around 100 feet tall at most but are more often around 65 feet tall in the city, though they can still develop massive trunks. The spring balsam odor associated with narrowleaf cottonwood is much less pronounced with this tree, but the two have a habit of growing 'rebel' sprouts — some pop out at the very bottom of the trunk, and others grow higher up on the main body of the tree. Like other cottonwoods, this tree is a water-loving species, most adapted to streamside conditions, but it can tolerate a degree of drought and the dry heat of Colorado summers.