Minnesota Tree Care Advisors

Characteristics
Disease Management

Eastern cottonwood has an extensive range across the united states; from North Dakota south to Texas and East to the Atlantic Ocean. This species is a bottomland species and this is where some of the largest cottonwoods can be found. The Minnesota champion is located in Chippewa County and its measurements are impressive. Height of the champion is 106 feet and the crown spread is 110 feet.

Large tree height:		80-100'

Canopy spreads:		40-60', Often a vase-shaped crown, but has the potential to spread widely.

Drought Tolerance:		Tolerant

Shade Tolerance:		Intolerant

Soil pH Tolerance:		Tolerant to high pH

Poor Soil Drainage:		Tolerant to flooding

Salt Tolerance:		Intermediate in tolerance to salt spray and Intermediate in tolerance to soil salts.

Leaves of eastern cottonwood are simple, typically shiny green, triangular (deltoid) in shape and the leaf has a flattened petiole

Compare the buds of balsam poplar with those of eastern cottonwood. Both are rather large, but the buds of balsam poplar are dark in color, sharply pointed and gummy with the red resin. While eastern cottonwood buds are rather green, typically blunt and the scales are held tight by a golden resin.

Not an important landscape tree due to its large size and its tendency to be a bit messy with twig drop, leaf drop and worst of all cottony seed.

Did you know
Important tree in the wild - it is a pioneer species and is also considered a nurse species since it provides shade and protection for species such as balsam fir.

DISEASE		SYMPTOMS	MANAGEMENT
Cankers, Valsa sordida (Cytospora chrysosperma), Phompsis sp., Hypoxylon sp., Mycosphaerella populorum, Cryptodiaporthe populea	Fungi	Fungi infect young twigs or wounds creating cankers on branches and trunks. Fruiting bodies commonly form on the face of cankers. Widespread and common on poplar, cottonwood, aspen and willow. Especially serious on Lombardy and silver leaf poplars.	Maintain plant vigor. Remove cankered branches during dry weather. Avoid wounds. Avoid planting in areas with poor air circulation. Trees prone to many cankers should be replaced with another tree species. CHEMICAL: None.
Leaf rust, Melampsora medusae and other species	Fungi	Yellow to orange pustules break through the surface on both leaf surfaces in mid to late summer. Angular yellow lesions may occur on the opposite leaf surface. Lesions turn black in autumn. Some defoliation may occur. Alternate hosts include hemlock, Douglas-fir, larch, and pine depending on rust species.	Choose a poplar clone with resistance. Keep susceptible conifers 500 yards away from poplar stock. CHEMICAL: Seldom necessary in landscape settings. Triadimefon or triforine.
Marssonina leaf spot, Marssonina populi	Fungi	Small brown leaf spots with yellow margins. Infection may advance into stem tissue. May be severe during wet seasons resulting in defoliation.	Collect and destroy leaves. Plant in areas with good air circulation. CHEMICAL: Fungicides seldom warranted in landscape plantings. NURSERY: Chlorothalonil at bud break and every 7-10 days if necessary.
Shoot blight, Venturia tremulae on Populus sp. and hybrids; V. populina on black cottonwood and balsam poplar	Fungi	Brown to black leaf spots rapidly expand on succulent tissue to cause shoot blight. Affected tissues dry out and become brittle.	Remove and destroy infected shoots. Increase air circulation. Rake and remove leaves in the fall. CHEMICAL: Seldom necessary in landscape settings.