They make an excellent accent plant for your home. My rhododendron has a black, sooty substance on its leaves and stems. The obvious indications that there are weevils present are the conspicuous notches around the edges of the leaves of the plant. Learning how to get rid of sooty mold on rhododendrons means getting rid of the pests that contribute to the fungal disease. Pests Causing Sooty Mold Leaves Scale – Scale insects commonly cause black fungus on rhododendron. Sign up for our newsletter. How do I calculate the amount of sod required. The black nymph lace bug also congregates on the leaf's underside, which adds to the black discolouration of the foliage. Usually the damage is aesthetic and plant health is not in jeopardy. Although the sooty mold fungus grows on the surface of the leaves and rarely causes permanent damage, it can seriously impact the appearance of the rhododendrons. It is flaking off some of the leaves and underneath they appear un damaged and shiny ( see photos). The bud eventually falls off and dies without blooming. Find more gardening information on Gardening Know How: Keep up to date with all that's happening in and around the garden. Why Did My Gardenia's Leaves Turn Black? Citrus Sooty Mold Info: How To Get Rid Of Sooty Mold On Citrus Trees, Gardening With Foil: How To Recycle Tin Foil In The Garden, Prickly Kale Leaves – Does Kale Have Thorns, Corn Husk Wreath Ideas: How To Make A Corn Husk Wreath, DIY Air Plant Wreaths: Wreath Making With Air Plants, Sod Webworm Lifecycle: Learn About Webworm Lawn Damage And Control, Cold Frame Construction: How To Build A Cold Frame For Gardening, Coral Bead Plant: Information On The Care Of Coral Beads, Hazelnut Growing: How To Grow Filbert And Hazelnut Trees, Thanksgiving Tradition: Turning Homegrown Pumpkins Into Pie, Growing Thanksgiving Dinner – Must Have Turkey Side Dishes, Interesting Uses For Pecans: What To Do With Pecans, The Bountiful Garden: Bringing The Garden To Thanksgiving. If the roots are mushy and black instead of firm and tan-colored, that means root rot has set in. The sooty mold itself does not injure the plant. Gardenias are my favorite flowering shrub. Be sure to consider where your rhododendron is planted. Determining the underlying problem is necessary to restore the rhododendron's health. Examine your plant carefully, using a magnifying glass if necessary to identify the culprit. Sign up to get all the latest gardening tips! This could happen due to the hot sun or cold winter winds. These micronutrients include iron, manganese, and zinc. They are small plants that can grow up to a height of 3 to 6 feet. Here’s how to help: Whenever the temperature gets above freezing, give your rhododendron a slow and steady trickle of water until the soil feels damp 8-10 inches down. Leaves are the best indicators of plant problems. To see if you have whiteflies, just shake a branch. This issue sponsored by: My rhododendron has a black, sooty substance on its leaves and stems. They all feed by piercing and sucking a plant’s juices. Chlorosis is a disease characterized by yellowing of rhododendron leaves. Bud Blast is a fungal infection that causes the buds on the Rhododendron to die and turn black before they bloom. Azalea leaves may be slightly more narrow and pointed than rhododendron bush leaves. They grow best in well-drained, evenly moist, acidic soil. Such yellowing can be caused by pollutants too. Severe infections can cause defoliation of the shrubs. It is often a homeowners’ first sign of trouble in the landscape. Treating with a fungicide won't help, but you could try to move the whole plant to higher ground or a raised bed to see if it can recover. This disease can be controlled by collecting and burning the affected leaves, and spraying the plant with a fungicide. These measures are only temporary, however, and the only way to keep the mold from returning is to treat the cause of the problem. Once you’ve identified the insect, you can select a control. It is often a homeowners’ first sign of trouble in the landscape. I always plant my gardenias near a window or door so I can enjoy the fragrant flowers even while I am inside. Rhododendrons are at their best in spring when they produce large clusters of showy flowers against a backdrop of glossy green foliage. So, it is always recommended not to plant rhododendrons in highly alkaline soil. These notches can be few or in some cases so extensive that the entire leaf edges end up being jagged and very unsightly! Scales species appear as white, gray or brown bumps on the undersides of the leaves. Foliage … If it is positioned as an understory feature with taller trees, your plant may not be infested itself, but merely be the honeydew recipient of an “abovestory” tree problem. The watchwords for you are vigilance and diligence to keep the insects from making your plant a five-star restaurant! The symptoms of bud blast on rhododendrons start with the bud turning a silvery grey color before growing black bristles. I have noticed on our rhododendron that the leaves are covered in a black substance. The leaves are small and dense. Click cover to read now! Mealybugs are soft, oval, 1/10-inch long insects with distinctly segmented pinkish bodies. black dots (fruiting structures of fungi) are sometimes visible in the center of the spot or in con-centric rings. and Botryosphaeria dothidea cause the stems and foliage to die. But if left untreated, it will shade the leaves, reduce growth, and invite other unwanted guests to dinner. Remove and destroy affected leaves. The fungal infections Phytophthora spp. There are various other rhododendron diseases, like leaf spots, and root and crown rot. Follow the control product’s directions for repeat applications. If a lot of cold wind blows past your rhododendron in the winter, it will curl its leaves inward so less leaf surface is exposed; the plant’s trying to keep water from evaporating out of its leaves. The leaves could also turn brown because of a lack of water. Within a few days, honeydew becomes infested with sooty mold.