Dogwood dying ?

Question: Leaves in my dogwood have brownish spots. Is this tree dying? Should I use copper fungicide?

responder: The Question Asker Replied May 08, 2023, 4:16 PM EDT
response: My dogwood leaves look droopy and moldy. Is it about to die? If so should I apply copper fungicide, neem oil, or do something else ?

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 09, 2023, 11:08 AM EDT
response: The leaf pictured might be showing early indications of infection by Elsinoe, a common fungal disease dogwoods can contract, particularly in cool or wet weather. (Although rains have been insufficient for much of this spring, dew on the leaves could still create enough of a moisture layer to enable spores to infect tissues.) Powdery mildew is another very common dogwood ailment that might be starting to manifest symptoms. The former fungus isn't usually severe enough to warrant treatment; the latter sometimes can weaken trees, though usually only after recurring years of moderate to heavy infection. You can visit our Key to Common Problems of Dogwoods page for more information and additional ailments you can compare symptoms to.  Some dogwood cultivars are more inherently disease-resistant than others, though none are immune. While a fungicide containing copper as the active ingredient might help reduce future infections, it will not be able to cure any existing infections nor reverse any current symptoms. Fungicide sprays have the potential to harm other organisms, including pollinators, and don't always work very well (especially if the weather is uncooperative). Plus, they typically need regular re-application well into the growing season to maintain their protective effects. Thorough coverage of leaf surfaces is required for good efficacy and this can be hard to achieve if a tree is mature or taller than you can reach. If you opt to try a fungicide, follow all label instructions carefully; neem oil might be labeled as a fungicide but it is not very effective compared to those products specifically intended for fungal control (since neem is usually an insecticide).  If a tree is large, consider hiring a certified pesticide applicator to make the treatments for you, as they will have better spray equipment. Fungal infection severity can vary from year to year based on weather, though, and might not require treatment to keep it suppressed for the long term. Other practices to keep the tree healthy will help it endure infection without treatment, including monitoring it for watering needs during periods of dry weather, making sure mulch isn't touching the trunk base, and avoiding impacts from lawn care such as herbicide use and liming too close to its root zone (dogwoods need acidic soil to thrive and certain herbicide ingredients risk absorption by the roots). As for watering, feel the soil about six inches deep in its root zone and water well only if it's becoming somewhat dry to the touch at that depth; if damp when probed, the tree likely has enough moisture. Dogwoods are sensitive to over-watering but also can be prone to drought stress during our summers and autumns, especially if growing in a lot of direct sun.  Miri