Some trees in the suburbs are in drought stress: What to look for and how to help
Some trees in the Chicago region seem to be dropping leaves earlier than usual. The culprit is the severe drought that has taken hold in much of the state since late May.
On top of the most recent dry conditions, experts say trees have been dealing with a build-up of stress over the last decade.
"We've had probably 10 or 12 years in a row where the weather just has not been ideal by any stretch of the imagination," said Sharon Yiesla, a plant knowledge specialist at The Morton Arboretum. "After that happens year after year, some of the trees are just more stressed than they were. Then you get a drought like we had this year, and that is sort of like the last straw."
Trees in drought stress often display symptoms like wilted foliage, yellowing leaves and premature leaf drop. This year, tulip trees and river birches seem particularly sensitive to the lack of moisture, Yiesla said.
To combat the long-term harm drought can have on trees and shrubs, Yiesla said, the plants need water to seep at least five or six inches into the soil, which can take longer than you might think.
While recent rains in Cook, DuPage and Kane counties have alleviated the "severe" drought classification in most of those areas, the counties are still in either "moderate" drought or "abnormally dry" conditions. Meanwhile, Lake and McHenry counties remain engulfed in the "severe" drought rating, according to the U.S. Drought Monitor.
The "severe" rating generally means that fire risk is heightened, water conservation is encouraged and crops are in danger of lower yields come fall.
To keep plants alive and healthy, including both young and old trees, watering is key.
"Water is always the first job in the care of trees, because everything happens because there's a good water supply: New buds are made for next year, leaves are maintained for this year, and if the trees are making seeds or fruits, they need water," Yiesla said. "Water, it's the kind of thing that people take for granted, but it's probably the most important thing we do for our trees."
It has previously been the opposite of a drought - excessive rain - that has damaged trees. Flooding rains like the ones we've gotten in the Chicago area the last two or three springs can cause root damage.
"It may not be that the whole root system has died, but there are damaged roots, and the tree is now working on a smaller root system," Yiesla said. "It takes time for that to grow back, and so that tree is not able to really pull water out of the soil as efficiently as it did before."
With trees battling everything from too much rain to too little, Yiesla said it's a good idea to keep an eye on your trees for any unusual symptoms.
Aside from drought, common ailments to look out for include canker disease, in which a tree's open wound has become infected by a fungal or bacterial pathogen. Tree scale infections - scales are sap-sucking insects that prey on most kinds of trees and plants - are also a frequent issue in the state.
For advice on trees, plants and landscaping, Yiesla and other plant care specialists at the Morton Arboretum's plant clinic can be reached at (630) 719-2424 or plantclinic@mortonarb.org.
• Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see dailyherald.com/rfa.