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Dogwood & Crepe Myrtle
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Date Posted: Wed, Oct 14 - 1:29 am
- We recently moved into new house in Museum District and there is a Dogwood tree in the back yard that looks stressed...This is a photo from a bit ago. I checked and it is not bone dry at 3 to 5 inches down in the soil, as I realize to much or too little water can cause issues. Could it just be that there is no protection from the sun/canopy above it? Thanks for any thoughts. Also, what do you recommend for crepe myrtle that is getting the white powdery stuff on the leaves. Thanks!
- Thank you for reaching out and for sharing the photograph of your dogwood! Looking at the photo, I can definitely see why you're concerned. The leaves appear quite curled and wilted throughout the canopy, which suggests the tree is experiencing some type of stress. You are correct that sun exposure could be contributing! Flowering dogwoods are naturally understory trees, meaning they typically grow beneath the canopy of larger trees. They prefer some protection from intense afternoon sunlight, particularly during our hot Richmond summers. A dogwood growing in full sun can be more susceptible to heat and drought stress. That said, there are a few other things I would consider before concluding that sunlight is the primary issue: 1. Continue monitoring soil moisture. You're already doing the right thing by checking beneath the soil surface! Check several locations around the tree, including farther out toward the edge of the canopy. The goal is consistently moist, but not waterlogged, soil. Deep watering when needed is generally better than frequent shallow watering. Also, check the drainage. Dogwoods prefer well-drained soil and can struggle when their roots remain excessively wet. If the soil stays saturated for extended periods, that could also contribute to the symptoms you're seeing. 2. Consider the root zone. Since you've recently moved into the home, it's difficult to know whether the tree has experienced previous root disturbance, soil compaction, or other stress. The nearby hardscaping may also contribute to increased heat around the tree. Maintain a layer of mulch. Approximately 2–3 inches of organic mulch extending toward the drip line can help moderate soil temperatures and retain moisture. Keep mulch several inches away from the trunk. 3. Avoid fertilizing for now. Fertilizer generally won't resolve environmental stress and could potentially make matters worse. Some resources about dogwoods: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/3010/3010-1484/3010-1484.pdf https://fairfaxgardening.org/dogwood/ As for your crape myrtle, the white powdery substance you're describing sounds like powdery mildew, a very common fungal disease on crape myrtles. Fortunately, powdery mildew is usually more of a cosmetic concern than a serious health threat to an established tree. A few things you can do to help: 1. Improve air circulation around the plant by selectively pruning crowded branches during the appropriate pruning season. 2. Avoid excessive nitrogen fertilizer, which encourages tender new growth that can be particularly susceptible. 3. Rake up and remove fallen leaves as part of your fall cleanup. 4. If the problem is recurring and severe, a fungicide labeled for powdery mildew on crape myrtles may be an option. These treatments are most effective when applied early in disease development rather than after leaves are heavily affected. Since we're approaching the end of the growing season, I wouldn't recommend treating the mildew now unless there are unusual circumstances. The tree will soon lose its leaves naturally. Resources for Crepe Myrtles: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/2901/2901-1040/2901-1040.pdf https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/430/430-451/SPES-387P.pdf
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Native Dogwood and Holly
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Date Posted: Sat, Jan 27 - 3:05 am
- Two questions about native plants: are red twig dogwoods native to VA? I have seen dogwoods with red twigs in the woods, but never like the ones you see around cities or in people's yards like "arctic fire" with the really red branches. Besides the nativeness of red twig, do they need a lot of sun or can they do well in partial shade? Also, is holly native to the eastern us or is it naturalized nowadays and brought over by the colonists? Thanks, Neal
- Hi Neal! Great questions, I'll do my best to answer them. What most people refer to as "arctic fire" I think is the red-osier dogwood (Cornus stolonifera Michaux). The nativity of this species in Virginia is questionable. It was historically reported to grow along the Potomac River in Fairfax Co., but supporting specimens currently appear to be lacking. It tends to do best in full sun to part shade with moist, rich soil. In nature, it is most often found growing in wet swampy areas. The silky dogwood (Cornus amomum P. Mill.) has a red/purple twig and is native to our area. American Holly (Ilex opaca Aiton var. opaca) is native to our area! It is common in the Coastal Plain and Piedmont areas but infrequent in the mountains. The digital Atlas of Virginia Flora is a great resource for checking what is native to our area: https://vaplantatlas.org/index.php?do=start&search=Search
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Powdery mildew?
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Date Posted: Fri, Oct 07 - 7:05 pm
- Hi. We have a white film on the leaves of two poppy plants we transplanted over a year ago. Cosmetically, it's not pretty. But don't know if it's harmful. It is only in the last 6 months that the film has appeared. They're under a dogwood tree, didn't know if that affected them. Can you tell me if this is harmful, and if it will impact the blooms? I don't see any buds so I fear this is a problem for the plants.
- Hello there, It sounds to me that you are dealing with powdery mildew. It's a very common fungal problem, heat and humidity aid its progress. It generally doesn't kill the plant, the plant just doesn't look it's best. I don't know which type of poppy you have but I'm guessing it's one of the oriental poppies (papaver orientale), that bloom in spring? You may want to consider transplanting the poppies to a spot in full sun with good air circulation. Cut back the foliage at the end of the season and dispose of it in the trash (not the compost pile). You don't want to be harboring the spores over winter. With some more sun and air, I think you will enjoy those poppies more. Good luck!