Autumn is usually the season we see leaves on trees start to turn lovely shades of yellow. However, you may have noticed recently the not-so-typical browning of the leaves on cottonwood and aspen trees in our area.
We have been addressing a number of concerns and thought it worth mentioning to all of our customers that these trees are sporting a bit of a different look this year due to a couple of fungal infections called Marssonina and Septoria.
These fungi love to show up when the weather is wet and cool, and we’ve had our fair share of rain this year.
Is this normal or cause for worry?
In most cases you do not need to worry if your aspen and cottonwood leaves have skipped over the yellow stage and moved straight to brown. To differentiate between normal autumn leaf color changes and fungal-related browning, consider the following:
- Weather: These fungi thrive in damp conditions, so this year’s weather patterns are playing a significant role in this phenomenon.
- Fungus Spots: Look for the presence of small, dark spots on the leaves. These are characteristic signs of Marssonina and Septoria infections.
- Leaf Drop: Healthy autumn leaf drop occurs gradually, with leaves changing colors before falling. Fungal-related leaf browning may lead to premature leaf drop.
What can be done?
Not to worry, the browning of aspen and cottonwood leaves caused by these fungi are not typically a major threat to the trees’ well-being. When caring for your affected trees, here are some recommendations:
- Yard Clean Up: To prefent further spread, thoroughly rake up and dispose of the diseased leaves and twigs. This simple step will aid in the recovery of your trees in the spring.
- Pruning: Consult with a certified arborist if your trees are displaying an excessive amount of defoliation or dieback. A skilled arborist will safely remove affected branches without causing more stress or damage.
- Maintain Tree Health: Ensure your trees receive ongoing care and maintenance with regular pruning and fertilization.
When spring arrives, you should see your cottonwood and aspen trees bouncing back with renewed vibrancy. If you have any concerns or notice any lingering issues, don’t hesitate to consult with a professional arborist for guidance on their recovery.
