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Posted on May 31st, 2024 in Forestry, Urban Forestry | No Comments »

Eastern cottonwood, fruit and white seed hanging from tree, Purdue Fort Wayne.Populus deltoides, more commonly known as the Eastern cottonwood, becomes a topic of conversation & complaint every year around this time.  A member of the willow family, this tree is found along rivers, roads, in parks, and around residential areas.  It grows to heights of 75 to 100 feet spanning up to 75 feet wide.  It prefers moist to wet well-drained soils but tolerates many types of sites.  Cottonwoods also produce small seeds with a tuft of cotton fluff (to assist with dispersal) that can number in the millions for a single tree.

That’s right, we are in the season of the cottonwood seed.  You may be walking or driving around or just looking out your window and it can look like winter is trying to attack with one last blizzard before summer sets in.  Seed production occurs between May and June for about 2 weeks with the floating cotton balls accumulating on roads and paths, in yards and parks, and in other locations with a little bit of grab.  Seedlings easily germinate, but are delicate, and in urban areas with an abundance of lawn care, many do not survive or are killed by excessive heat or rain.

Many concerns that I hear about are clogging of waterways or air filters, and the worry of fires.  Seeds usually flow easily downstream without the volume or mass to clog waterways.  They can accumulate on air conditioner units or other filters but are easily cleaned off.  Cottonwood seeds are highly flammable, can pose a risk in drier climates, and should not be ignited to clean them up.  They can be cleaned like leaves with fine-tined rakes or picked up in clusters and bagged.  The good news is this usually only lasts for about 2 weeks.

If you do have any questions about managing your cottonwood trees, feel free to contact your local extension office or you can search for ISA-certified arborists in your area at Find an Arborist.

ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel (Invasive White Mulberry, Siberian Elm, Tree of Heaven)
Eastern Cottonwood, Article, Purdue Fort Wayne
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel (Against Invasives, Garlic Mustard, Autumn Olive)
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel (Common Buckthorn, Japanese Barberry)
Trees and Storms – The Education Store, Purdue Education’s resource center
Planting Your Tree, Video, The Education Store
Tree Installation, The Education Store
Indiana Invasive Species Council
Indiana Department of Natural Resources: Invasive Species
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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