Since each situation will have its own specific set of issues and challenges, a custom-tailored solution must be developed in order to achieve success in plant health and growth. Try Pennsylvania Cooperative Extension Service. Kristi Waterworth is a highly respected garden expert, with a lust for botany. But maybe youre concerned that your kousa dogwood just isnt growing as it should, or generally doesnt look healthy to you. Thanks for your question! Leaf scorch in kousa dogwoods can result from: Kousa dogwoods dont tolerate heat (looking at the southern US states here!) . During times of drought water every 7 to 10 days. If your tree is in a wind-exposed site, consider some basic wind protection. Additionally, you can spread bark mulch around the base of the tree to keep the soil from drying out. Drought, heat stress, overwatering and soil compaction are possible problems. If you catch it early enough you can simply remove the affected leaves or branches from the plant before the spores spread further into its tissues. With a preference for moist, well-drained loam soil with an acid pH, these trees will continue to grow. Could this be related to the damage or the heat waves this year? Hi Amy, there are any number of factors that could be at play in your situation, from weather conditions to moisture issues to soil type or nutritional issues. I would suggest a well-set drip irrigation system for your garden. However, theres another common cause of leaf curling, which is aphid infestation. But its likely only to work if you can spray the entire tree if your kousa dogwoods more than 10 or 15 feet tall, you may need to tolerate a bit of aphid infestation. Generally, white dogwood cultivars are more susceptible to spot anthracnose than pink cultivars. The most common issue with kousa dogwoods. Is that a problem? Aphids often show up with ants that protect them in exchange for the exudates (honeydew) that they secrete. After that, shake the mixture properly. It has been hot in NJ this summer like the rest of the country. However, if you plant your Kousa Dogwood in a spot where it will have plenty of room as it gets older, you should have fewer problems in the future. And there you go. Aphids are simple to control with daily sprays from a water hose. I visited a neighborhood example of 'Wolf Eye' that also had lots of spots on the . Controlling fungal attacks is not easy. Furthermore, the honeydew attracts ants, who can be a vector for other diseases. Watering from overhead and even rainfall contributes to powdery mildew. In drought, they undergo leaf curling, also caused by aphids, and leaf scorch. Id really hate to dig it out because this is the first time in five years that Ive gotten a bract, yep one single bract. annuals Kousa dogwood (C. kousa) and hybrids of kousa and native dogwood (C. florida) are resistant to anthracnose and decline and should be used to replace dying trees. Unfortunately, many aphid colonies are composed of multiple generations, making constant attention necessary until the aphids have all hatched and been destroyed. Fertilizer Patches of gray mold grow on the patches if the weather remains very humid. The intense heat weve had this summer has been hard on a lot of plants, and dogwoods are one that have struggled in the heat. are known throughout U.S. Department of Agriculture plant hardiness zones 2 through 9, depending on species. Well, it varies from plant to plant. You can control aphid infestation fairly easily if your trees small enough to get at. Make sure there is 1-3" mulch over the roots to keep the soil cool, moist and the weeds out. They are so disease-resistant that you can cut them to the ground in early spring and theyll grow back healthy as ever. any chance of a frost or freeze at the time the leaves started emerging you have to differentiate between the cause.. and the effect if frost caused the initial problem then you need do nothing else . if the damaged leaves.. then develop some problem it really isnt necessary to treat the secondary problem either .. most trees can reflush at least once after a severe frost.. without any long term problems did you have a horrible winter ??? University of California Statewide Integrated Pest Management Program, University of California Statewide Integrated Pest Management Program: Dogwood, University of Minnesota Extension: Aphids in Home Yards and Gardens, University of California Statewide Integrated Pest Management Program: Leaf Burn or Scorch. Make sure there are no rocks at the bottom of the hole. Les Engles achieved Master Gardener through theCamden County Extension of the Rutgers Master Gardeners Program. Hellebores (Not the month you think), How Far Apart To Plant Hostas (Explained), Why is Agapanthus Not Flowering? So, stay aware during that part of the year. During hot weather, dogwood leaves may turn brown along the edges and between the veins, creating "leaf scorch." Drooping, reddening, and curling are additional symptoms . This will direct water straight down into the root system and alleviate stress. Kousa dogwoods dry out easily because they have a shallow root system. A bigger tree close to your Dogwood will offer partial shade. Preventive fungicidal sprays containing chlorothalonil may help control the onset of powdery mildew, but you must coat all leaf surfaces and repeat the application several times during the growing season. The tree gets plenty of water but I doubt the roots stay wet. Its underwatered which might show itself in leaf-curling see below. Make sure the soil has the right amount of nutrients in stock. Its a great choice for tough urban landscapes because it is tolerant of drought, shade, pollution, salt air, and urban heat island effects. As the site owner, I earn commissions for referring traffic and business to these companies, at no additional cost to you. Aphids are tiny, sap-feeding insects that plague landscape plants. When you knock these slow-moving pests from the leaves where they're feeding, they can't reattach quickly enough to survive the journey back. Thank you! Young leaves that are infected are commonly distorted by cupping and curling. 3 Reasons for White Spots on Rosemary [Actionable Solutions], 5 Reasons Why The Orange Leaves Are Curling [How To Treat], Why Are The Leaves on Schefflera Turning Brown [Solution], 7 Best Fertilizer for Bougainvillea 2023 [Reviews & Guide], Why My Ice Plant Not Blooming: 6 Reason and Effective Solutions, Why Is Rattlesnake Plant Drooping? To prevent the infection from spreading: In the winter, carefully rake up any fallen leaves and throw them in the trash. Water: Average water needs, but will require irrigation during a drought, especially if planted in full sun. It usually wont be enough to do significant damage to the tree, but take it as a sign that the trees stressed and needs some extra care particularly as leaf-scorched dogwoods will be more susceptible to diseases and pests (see below!). Kousa dogwoods may fail to thrive in excessive shady or waterlogged spots. Perennials When you buy with our links, we may earn a commission. winter. Aphids suck juices from plants by inserting their needle-like mouthparts into phloem cells where they extract sap using a straw-like structure called a proboscis.. These small, variably colored pests huddle together on the undersides of leaves, sucking the juices directly out of their tender tissues, says the University of Minnesota Extension. Doing this will help you decide if your tree can benefit from a general fertilizer or if it needs a fertilizer that is aimed towards a specific nutrient. Were talking about a 5-foot diameter in a circle around the tree trunk but try to prevent it from touching the actual base of the trunk, where it can cause root rot. I have covered the reasons, scientific explanations & DIY solutions. Overwatering the tree (or poor drainage) can also cause chlorosis. So stay aware during that particular season. All of these viruses infect plants through insect vectors like aphids or leafhoppers; major sources of disease spread among ornamental plants throughout regions plagued by these insects. Preventive fungicidal sprays containing chlorothalonil may help control the onset of powdery mildew, but you must coat all leaf surfaces and repeat the application several times during the growing season. If lots of leaves are infected, you can get some defoliation (leaf drop). Keep watering the tree and feed it early next spring and it should rebound and put out some more new growth. Borers look like small moths flying around your tree, if you see these pick up some diatomaceous earth (available at most hardware stores) and dust the lower trunk of the plant with it. Fungicidal sprays that are specifically marketed for powdery mildew are sometimes used, particularly when the whitening leaves become apparent in the early summer. They get top-heavy and can easily be blown over in a storm or strong wind. Is there a disease or insect problem I should be worried about? Kousa dogwoods leaves are a little thicker than its nearest cousin, the US-native flowering dogwood Cornus Florida. Moreover, Nowadays, sticky trapsare found to be highly effective against aphids. Kousa dogwood ( Cornus kousa Hans.) Edibles If you do find them on your Kousa dogwood give your plants a good blast of water from the hose with some added soap or insecticidal soap early in the season to get rid of these pests quickly if only a few are present. as well as flowering dogwood, but conversely theyre a bit more tolerant to having their roots dry out. Use Vitamin B-1 (available inexpensively at Vander Giessens) twice a month through the summer to reduce stress and promote vigorous rooting. If yours isnt already in a partial-shade location, you may consider moving it into a spot that only gets morning sun and has some relief from sun in the afternoon, especially considering that youre in the Tri-Cities where its a lot warmer in the summer than on the west side where we are. Curling, deformed leaves are another sign of powdery mildew. My dogwood bush is about three years old and hasn't flowered yet. Summer Well, leaf curling is a defense mechanism of Dogwood leaves to avoid heat stress. Well, it varies from plant to plant. Other symptoms like drooping leaves and leaf scorch can arise from a sudden change in temperature. Insect Control As the disease progresses, the leaves may cup or curl upward. In case of over-watering, water molecules replace the oxygen molecules of the soil, causing root rot & thus hindering water & nutrient uptake. Some species, such as the kousa dogwood (Cornus kousa; USDA hardiness zones 5 through 8), cup their leaves in response to adverse weather, but cupping leaves is a common problem for all dogwood species. If you see the white coating and cupped leaves on your tree, fungicides cannot cure the disease, which is already established. This is a protective measure to try to reduce further water loss by transpiration. You can also reduce the risk of fungal leaf spot infections by. Jack's Throughout the whole year, you may have noticed that summer is the time when Dogwoods show maximum leaf curling. 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