Is Hot, Dry Weather Affecting Your Dogwoods?

A homeowner who purchased a dogwood through the Nashville Tree Conservation Corps’ Farm-to-Yard Tree Sale contacted us concerning a problem with the tree: it looked sick and its leaves were rapidly turning brown. Did the tree have a disease or some other problem?

A close, on-site examination by Bo Arrington, NTCC board member and certified arborist with Bartlett Tree Experts, brought a quick diagnosis: leaf scorch caused by heat and lack of water. Samples sent to the Bartlett lab confirmed that no fungal pathogens were present.

Young dogwoods are susceptible to two fungi: anthracnose and powdery mildew. These fungal conditions tend to be exacerbated by wet weather, but in Middle Tennessee we’ve been having just the opposite problem — warm, dry spring seasons followed by scorching hot, dry summers. If your dogwoods and other trees are showing signs of stress right now, chances are it’s from insufficient water.

“If the leaves of your tree are browning from the tip back, it’s a sure sign of water stress,” Arrington says. The leaves of a dogwood that’s not getting enough water and being blasted by the sun will turn brown from the tip, feel thin and crispy and eventually fall off. Anthracnose, in contrast, brings a blotchy pattern to the leaves, while powdery mildew leaves white or gray patches.

With the record-setting heat Nashville has been experiencing, Arrington says the dry weather conditions that typically don’t arise here until July or August are being seen earlier in the year. As a result, many trees are showing signs of stress, including magnolias and dogwoods. And the only solution is to water your trees, especially young ones.

“You need to manage the soil moisture. There’s no good formula to tell you exactly how much. The best way is to stick your fingers directly into the soil,” Arrington says. Heat, wind, soil conditions, and the amount of sunlight your tree gets will all influence how much water it needs.

How and When to Water

Arrington also offers these reminders about best practices for watering trees:

• The best time to water trees is in the morning.

• Infrequent deep soaking is better for trees than frequent light watering since it encourages deep root growth.

• Let the soil around your tree dry out between waterings.

• Watch your trees carefully, and check the soil for moisture levels and water when necessary. In extreme conditions like our June heat wave, that could be as often as 2-3 times per week.

Keeping a close eye on all your trees can help to prevent small problems from turning into big ones. Subscribe to our newsletter to receive regular updates on tree care and tree policies in Nashville.