In parts of Colorado Springs, lots of trees are taking on a greenish tinge over the past two weeks. People have asked me “What is that tree that leafs out so early! I have to get one!” (or variations of this).
Well….one of our craftiest trees actually develops and drops its seeds before it puts out its leaves, and those seeds are a beautiful spring green when they first show. Over the next few weeks, they will turn to tan and then a good wind (and we do get good winds, don’t we?) will blow them out of the trees, scattering them everywhere. And then, it begins. Any spring moisture, including from your sprinkler, will have them sprouting everywhere. I’ve had them growing in my gutters, and even had one get started at the bottom of my car windshield one year!
This tree is the (dunh, dunh, DUNH!)…..
Siberian Elm (Ulmus pumila)!
Sometimes this tree is commonly called Chinese elm, but that is unfair as there actually is a Chinese elm (Ulmus parvifolia) which is quite lovely, known for its beautiful bark. However, those of us who live in the older parts of the city are very familiar with the Siberian elm. Most of the Siberian elms downtown and in Old Colorado City probably started as volunteer seedlings. They grow rapidly, which causes their wood to be pretty weak. This means twigs rain down when the tree is even slightly stressed, and branches snap off easily under snow or when it is windy. These trees always have a collection of debris below them, making lawn mowing fun if you have one nearby.
Now in fairness, the American elm (Ulmus americana) is also putting out bright green seeds right now too. But the number of American elms in our city has dwindled, thanks to Dutch elm disease and drought, and the seeds are not nearly as successful in germinating.
So take a closer look at the trees you think are leafing out. It’s a good possibility that you’ve found a Siberian elm “in seed.”
Submitted by Carey Harrington, Certified Colorado Gardener and Colorado Native Plant Master