Saturday, April 14, 2018

Non-Native Shrubs Shade Out Spring Wildflowers

This time of year, you can tell with one glance how many non-native shrubs are growing in a local woodland. Non-natives like privet, winged euonymus, and bush honeysuckle leaf out earlier than most native shrubs, reflective of their having evolved in a different climate from our own. Many of our woodlands are now thick with these non-native shrubs, and their early leafing out has ecological consequences. The spring ephemeral wildflowers have evolved to utilize the sunlight available during that window of time in spring when the woody plants above them are still dormant. Introduce woody plants that leaf out earlier, and the wildflowers can't store up enough energy to bloom the next year.

This problem will be exacerbated as we lose the many ash trees in our woodlands, since the nonnative shrubs will likely grow all the more densely as more sunlight reaches the understory in summertime. At Herrontown Woods, we're cutting down the non-native invasive shrubs, to allow more sunlight to reach spring wildflowers, and also to allow native shrubs a chance to thrive.


  1. On May 12, 2016, Stephen Hiltner published a picture of a viburnum titled "mystery shrub." I am in the process of helping a neighbor do a plant inventory on a woodlot near Knoxville, TN. This spring we discovered several specimens of a Viburnum sp. that is a perfect match to the photo published by Steve. I am curious to know if the "mystery shrub" found at Princeton has been identified. I have examined many hundreds of pics of viburnums, and the only one that matches our specimens is the Princeton specimen. Steve, if you happen to see this blog, I would appreciate hearing from you. Thank you.

    Best regards,
    Charles Pless

  2. A botanist by the name of Michael Donoghue emailed me the identity: Viburnum setigerum ("Tea Viburnum"). Thanks for your comment. I had forgotten about the mystery shrub, and will write something up.

  3. Many thanks to you and to Michael, I wonder if this particular species is especially invasive. I like the color of the leaves. In fact, I wouldn't mind having a shrub in my lawn if it could be pruned so that it would be less spindly than in the forest habitat. I'm happy that I found your site -- thanks to the mystery shrub. Make more videos!!!! There is something about a nature walk that invigorates.