A few weeks ago, some of the earliest green could be seen appearing on trees in our neighborhood. It’s always exciting to see those first tree leaves coming along isn’t it?
Well….the fairly invasive Siberian elm (Ulmus pumila) – pretty much the best example of a “trash tree” in our area – likes to play a little trick on us. The tiny bits of green we see covering them are actually their ripening seeds.
The trees pollinated weeks ago, and then they get a real jump on the season by putting out thousands and thousands of seeds before they even think of unrolling the new season’s leaves. The seeds green up, then turn tan, and then, in those windy April and May days, they leave the tree and spread over a huge area. Sometimes this strategy backfires when a late hard frost kills off the seeds before they can fully mature. But this year, it looks like we will have a bumper crop of Siberian elms.
The trees grow rapidly with brittle wood that breaks easily. One source says it drops twigs “when stressed.” From my experience, they must always be stressed! They aren’t one of the best trees for our landscapes, so feel free to pull those seedlings!
Contributed by Carey Harrington, Certified Colorado Gardener, Colorado Native Plant Master