Have you noticed that our state tree, the yellow poplar, is looking less than stately right now? All around the bluegrass, yellow poplar leaves have been turning yellow and dropping. Interior leaves seem most affected, but this yellowing is relatively evenly distributed from top to bottom of the tree canopy.
While there are several insects and diseases that can affect yellow poplar, the yellowing we are currently seeing is an environmental issue and demonstrates yellow poplar's response to stressful conditions. Recently we have had very hot weather with many areas receiving little or no rain. Yellow poplar's response to this "mini-drought?" Drop leaves and conserve resources.
You may be wondering why yellow poplar is stressed by normal summer conditions if it is a native tree. While yellow poplar is well adapted to the summer, it prefers to grow in deep, rich, moist soil that is well-drained--which is not the typical condition in many lawns and parking lot planting beds. Yellow poplar in the bluegrass is at a disadvantage because it does not thrive in our soils or in the landscaped settings where it is typically planted. While it may still grow well in general, it will be more susceptible to environmental, disease, and insect stress than if it were growing in its ideal location. Trees in the forest haven't shown these symptoms (although they may have leaf problems from other issues like the yellow-poplar weevil).
The good news is that yellow poplar is resilient, and trees with these symptoms will likely recover well. In fact, many trees that were severely affected only a couple of weeks ago are already improving. Yellow poplar puts out leaves to replace those lost, and it is not likely that this mid-summer leaf-drop alone will adversely affect the long-term health of trees. However, if drought is prolonged or if other stresses are severe, it could be a more significant issue for the tree over time. Either way, if you (or your neighbor) have a yellow poplar, it's probably time for some summer raking!
Educational programs of the Cooperative Extension Service serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, religion, political belief, sex, sexual orientation, gender identity, gender expressions, pregnancy, marital status, genetic information, age, veteran status, or physical or mental disability.