You see, cottonwoods are in bloom right now and cottonwoods, like people, come in male and female models. Male flowers are colored red, while female flowers are yellowish green. Cottonwoods don't start blooming until they are at least 15-20' tall, and they tend to bloom only in the upper parts of their canopies, so most people don't notice cottonwood blossoms at all. Once you know what you're looking for, though, they are easy to recognize.
One of my favorite finds is multitrunked cottonwood trees where part of the tree is male and part of the tree is female. These grow where several seeds sprouted in close proximity to each other, giving the appearance of a single plant. In this photo of an example east of Clearwater, you can tell there are two trees, but the canopy melds together into one whole. The male tree is on the left and the female tree is on the right.
If you watch the ground under cottonwood trees at this time of year, you can see the blossoms up close after they fall from the tree - especially the males. Here is a bloom that I found just this morning on a walkabout in the back yard. It's about 2 1/2" or 3" in length overall.
I love cottonwood trees. Their shining, dancing leaves rustle in the slightest breeze and seem to cool me during the summertime with both their motion and their gentle whispers. The trees grow rapidly and are wonderful wildlife habitat, attaining a stature in the landscape that really satisfies me here on the prairie.
Cottonwoods have received a lot of bad press lately, though. My personal opinion is that the quest for a "cottonless" cottonwood is greatly to blame. Obviously, for a cottonless cottonwood, all you need is a male tree. The current crop of selected cultivars, though, does not seem to do well in the Wichita area past about 15 years of age...which means that just as the trees are looking like true trees, they get infested with cottonwood borers and die.
My solution? Learn to live with the cotton. It's really quite beautiful during its season, and several bird species use it to line their nests. If you accept that cotton is a part of life on the prairie, you can simply transplant seedling cottonwood trees with local genetics and enjoy this graceful, giving tree for many years. Who knows? In 15 years, you might even discover that you got a naturally cottonless male!