cottonwood1.jpgIs it just me, or have the cottonwoods really dragged out their “cottoning” season this year? (I’m sure that must be a word, and if it isn’t, it should be. I’m sure you know exactly what I mean!)

In the past, the cottonwoods in my neighborhood and in Monument Valley Park all seemed to dump their cotton on us in the first two weeks of June or so. I would go to the park for a jog and come back with cotton stuck all over me (I just hate it when it tries to go up my nose!). But I started noticing it this year in late May, and then it kept going, and going, and going.

In late June, I took groups on plant walks in the park, and cotton was still blowing around and gathering at the edges of all of the paths. But we were astonished to see HUGE clumps of cotton hanging from the branches of the trees! Why had I never noticed this before? Does it always happen this way?

cottonwood2.jpgIn the second week of July, I took a trip to Crested Butte and happened to hit a BIG cotton day there as well. As we ate lunch on the patio of a cafe, a female lanceleaf cottonwood showered us with fluffy puffs of cotton. I’d never noticed that cottonwoods grew there before. At 8880 ft, the town of Crested Butte really is just at the top of the range for these trees. And when I returned home, cotton greeted me once again in the park! I’m starting to wonder if we’ll have cotton instead of snow in the park this winter.

In the past year, I became quite interested in the cottonwood trees in Monument Valley Park when I realized all three native species grow there – the plains cottonwood that everyone knows with its huge, nearly triangular leaves (Populus deltoides), the narrowleaf cottonwood with its narrow willow-like leaves (Populus angustifolia), and the lanceleaf cottonwood, a naturally occurring hybrid of the other two (Populus x acuminata). (Although it’s a hybrid, it may be self-fertile and able to reproduce from its own seed.)

When I started noticing the extended “cottoning” this year, I had a theory that the different species were releasing cotton at different times. But this was before I actually looked up into the trees themselves to discover the huge clumps of cotton. Females of all three of the species had these clumps in late June. And in Crested Butte in July, I saw female narrowleaf and lanceleaf cottonwoods with the clumps. (Plains cottonwood don’t grow at Crested Butte’s altitude.)

Some of my research has indicated that cottonwoods traditionally release their cotton with the late spring winds, taking advantage of spring snow melt and run-off that will catch and carry the seeds far from the mother trees. Now this makes sense for the trees in Crested Butte. Snow has been slow to melt this year in the mountains above the town, and the rivers are just now getting to where they are running high. But in Monument Valley Park?? Really, it’s just been dry, dry, dry. In fact, there were plenty (PLENTY) of late spring winds as well (not to mention strong and plentiful early and mid-spring winds too). It’s almost like the trees waited for those to pass.

Well this remains a mystery to me for now. But in addition to reading everything I can about cottonwoods, I’ll certainly be watching these trees more closely from now on and recording when they “cotton.”

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