These common deficiencies may cause leaf spots: Calcium. During mild and wet weather in the spring, new infections are initiated. Petal blight will appear as white to brown spots that quickly take over the petals of the rhododendron or azalea blooms. Kimberley McGee is an award-winning journalist with 20+ years of experience writing for a variety of clients, including The New York Times, Las Vegas Review-Journal Home section and other national publications. Any brown leaves will drop off as the new growth emerges. One of the most common creepy cruds that cause issues with azaleas and rhododendrons is a fungus known as water mold. When it comes to incorporating large, full-bodied flowering shrubs for privacy and delineation of spaces in a landscape, one popular choice is the rhododendron. There are several types of fungus that can cause this. Prune both plants after the bloom period to assist in next year’s big production of brilliant blooms. Check the underside of the plant’s leaves on a regular basis. Azaleas and rhododendrons like to have a layer of mulch to protect the shallow roots of the plants. If you see your rhododendron leaves turning yellow, review each and every element of the plant’s care. To control the damage that can be done to rhododendron leaves by the insects that immigrate to your garden, you need to control the population of these pesky invaders. Leaf spots: Purple or brown, more or less round spots appear on the upper leaf surfaces, usually of evergreen species. Control Phyllosticta leaf spot disease by raking up all fallen leaves and avoiding the use of overhead watering to prevent wetting of the leaves. Plan the perfect garden with our interactive tool →, Rhododendron image by Jan Ebling from Fotolia.com
, North Carolina State University: Rhododendron Diseases, University of California Agriculture and Natural Resources: Rhododendron, University of Massachusetts Extension: Rhododendron Leaf Spot (Several Pathogens). This kind of damage is most likely due to unfavorable environmental and weather conditions. Don't hose down the plant from the top down. You’ve put in the work and waited all year for the blooms to begin on your rhododendron or azalea. The spots are typically outlined by a dark brown edge. Some ... Rhododendron leaf-miner (Fig. It seems to be happening in sections of the plant. in Journalism from the University of Nevada, Las Vegas. Although it’s unsightly, leaf spot is only a significant problem on poorly growing or unhealthy plants, which might end up dropping a substantial number of leaves. A second type of Rhododendron issue is brown spots on the leaves. Learn which plants thrive in your Hardiness Zone with our new interactive map! If your rhododendron is planted in a spot that receives direct winter winds, consider building a burlap wind barrier around your plant. From bright pinks to deep golden hues, there are many different rhododendrons and azaleas from which to choose that require a little less maintenance to keep disease and blight far from its foliage and blooms. Rhododendrons are favored for their large, paddle-shaped leaves that create a showy specimen in your garden all year long. The first one that comes to mind is Cercospora leaf spot, a … There are several diseases that could cause black spots on your rhododendron, but one of the most common is Cercospora leaf spot. Rhododendrons can be affected by a condition called "physiological leaf spot." This condition is caused by poor root health, improper irrigation as in over- or under-watering, drought and extreme heat exposure. It can be hard to know if what is blooming in your backyard is an azalea or a rhododendron. Any rose fungicide will do: myclobutanil (systhane), fungus fighter, roseclear etc. Brown spots on Azalea leaves are common yet treatable. This condition is caused by poor root health, improper irrigation as in over- or under-watering, drought and extreme heat exposure. When the fungus kills an area of the leaf the dead tissue drops out, making it look like something is eating the leaf. Knowing what causes brown spots and understanding how to prevent and treat them may save your rhododendrons from irreversible damage. Rhododendron lace bug – Chlorotic spots on upper leaf surface, numerous dark spots of insect excrement on lower leaf surface; small, dark, spiny insects and slightly larger (3-mm), lacy insects on lower leaf surface. There are a few things to do to keep rhododendron diseases from occurring in your green spaces. Brown spots on Azalea leaves are commonly caused by a … Note: the other rhododendron, which is planted in the same soil about 1 metre away, is doing fine, so it can't be the soil acidity can it? This includes balancing the soil condition at the proper pH range and adding fertilizers, mulch and adequate watering. Phyllosticta leaf spot is a fungal disease that causes small dots of yellowish-tan to brownish spots on the rhododendrons leaf surfaces. Brown spots on rhododendron leaves may not be a sign of disease. Dark-brown, pimple-like fungal fruiting structures form within the spots. Spots may become tan in the center and may have a yellow halo. But I started seeing browning of some of the leaves. There are some things you can do to prevent curled, crispy rhododendron leaves and repair damaged plants. Now the leaves are turning a rust color, curling upward, and falling off. By identifying the type of fungi that has selected your rhododendron as a sweet spot to thrive, you can be sure to eradicate it in the shortest amount of time and without further damaging a healthy rhododendron. The two primary reasons that rhododendron leaves turn brown are cold weather and rhododendron wilt. The main cause of unsightly foliage or a lack of flowers is fungi. Can you help me with my rhododendron? If you feel the need to fertilize, do so sparingly and with something organic instead of the blue colored liquid soluble fertilizers. brown spots on rhododendron leaves Most gardeners, whether new to the art or seasoned growers, have come across powdery mildew on plants. Properly dispose of the infected plant parts far away from rhododendron shrub. Preventing disease from the start is much easier than getting rid of it or controlling it from spreading to healthy plants. Rhododendrons grow best in soil that is consistently moist but never soggy. This pesky insect lays its eggs on the developing flower buds and moves on to surrounding plants. Analyze summer watering systems to be sure plants are getting well soaked down into the roots. The peak season for rhododendrons is early spring and late May. Even pests like aphids, bark beetles, spider mites, scales, weevils, and caterpillars can attack this plant. Bud blast is spread by the rhododendron leafhopper. The canopy of the rhododendron can look healthy and full and the buds big and bulbous, but you can still have a fungus lurking within the plant. Burnt rhododendron leaves (leaves that appear burned, scorched, or browned and crisp) are not necessarily diseased. With the humid summers here in SC, I always seem to have at least one Rhododendron with this problem. Infected leaves … It is spread from plant to plant via airborne spores and is difficult to control outdoors and indoors. Inspect the leaves weekly, particularly in warmer months. Prune your rhododendrons in the fall or late winter/early spring before the flowers bloom to promote adequate air circulation through the shrubs to keep their leaves and flowers dry and aerated, according to Daniel H. Gillman, plant pathologist of the University of Massachusetts Extension landscape, nursery and urban forestry program. Naima Manal's articles on health, diet, nutrition, alternative medicine, education, parenting, crafts, travel, home and garden and home improvement have appeared on various websites. There are many types of fungi in search of healthy rhododendrons to feed upon. They sometimes contain numerous small, black fruiting bodies of the causal fungus; Rust: Discoloured spots on the upper leaf surface correspond to pustules containing dusty orange spores on the lower surface Rhododendrons and azaleas are some of the most popular spring-flowering shrubs in the landscape, and healthy plants can give years of pleasure. You can also use products that contain imidacloprid or dinotefuran to spread around the soil to keep creepy crawlers from making purchase in the soil or climbing up the lower branches of the hardy rhododendron or azalea. Winged pests can also create issues that often appear in spring and summer as they migrate from garden to garden. This can leave the healthy plant open to even more serious diseases that can take it down to the roots. The symptoms of bud blast on rhododendrons start with the bud turning a silvery grey color before growing black bristles. As stated by R.K Jones and D.M. Benson, plant pathologists at North Carolina State University, infected leaves will have a "water-soaked" appearance; then they will become dried out and fall off of the shrub. Symptoms: Earliest symptom is light brown or whitish coloured circular spots on petals. Spots enlarge to form irregular blotches until whole flower collapses. The fungus will show up as light-green, yellowish or reddish-brown, almost scorched-looking spots on the tops of the leaves. These show up on older, mature vegetation near the bottom of the plant. Remedy: Avoid overhead watering. The most common include: Each unsightly fungus has its own set of issues with which a gardener needs to contend. Most of the plant is OK -- the diseased leaves appear on the ends of some branches, but not others. These flowering beauties belong to the Ericaceae, heath, family and are sometimes affected with brown spots on their leaves. While the bushy evergreen offers a spot of color in the garden all year long, it can be hiding problems that will pop up on the leaves or blooms as the weather warms. This is more than likely a sign of bud blast. For about 11 months of the year, rhododendrons show us only their evergreen leaves. Do Time to act in December. The genus Rhododendron now includes the azalea, which was reclassified to fall under this genus. Now on one of the plants the leaves are starting to not look good. Do not let the leaves fall to the ground to infect the soil. Look for discolored roots or wilted branches. Each is prone to the same types of leaf problems. During Summer, it is recommended that you check plants under eaves where rainfall may not penetrate even on the wettest days. While leaf spots can be controlled with a fungicide, root and crown rot can be prevented to some extent by planting rhododendrons in well drained soil. It will spread under the leaves unnoticed before typically appearing as unattractive spots on the top of the leaves. However, there are many different types of rhododendron. )-Leaf Burn. The infected blossoms will look limp and somewhat wet but not from dew or a recent rain. It can be rather disheartening when the otherwise-healthy buds on a bushy rhododendron promise an incredible show and then begin to discolor and shrivel away. At the first sign of brown spots, whether caused by an infection or a physiological problem, remove the affected leaves before the spots spread beyond the initial sites to the rest of the plant. Diseased flowers dry up and cling to the plant (leaves and stems are not affected). More information on successfully growing azaleas and rhododendrons is available in the fact sheets HGIC 1059, Azalea Care; HGIC 1058, Azalea Planting; and … Look for yellow leaves, scorched brown spots, powder or discoloration. The symptoms of azalea leaf gall are varying sizes of sores on the leaves. Petals feel slimy when rubbed between fingers. If you see discoloration on the plant, mites are more than likely the issue and need to be removed with either a homemade or commercial insecticide. Properly dispose of the infected plant parts far away from rhododendron shrub. The latter is … This is specifically one of the most common ailments that affect azaleas and rhododendrons. A fungal disease that causes irregular brown spots on the leaves, usually attacking lower leaves first. Rhododendrons can be affected by a condition called "physiological leaf spot." This can cause the spores to spread or can push pests down into the soil only to return. This windborne spore reinfects only rhododendron. Her full bio and clips can be viewed at www.vegaswriter.com. Tropical regions of southeast Asia and northern Australia will also be good homes for rhododendrons. Phytophthora thrives in wet soil or poorly drained areas where the plant is installed. Any suggestions as I don't want to lose this plant. But when you can see brown spots where the leaf tissue hasn't fallen away yet, you know that it's a fungal problem not an insect problem. Get in close and investigate the plant. There are various other rhododendron diseases, like leaf spots, and root and crown rot. Previous. The infected parts are invaded with brown spots that expand and spread from the leaves and to the stems to infect the established rhododendron leaves. I have an established Rhododendron that is showing brown, dried, drooping leaves with black spots this Spring. How to Prune Lower Branches of a Rhododendron, Organic Treatment for Apple Tree Diseases, Gardening Know How: Azalea Insect Problems – Lace Bug Damage To Azaleas, Gardenia: Hardiest Azaleas and Rhododendrons, Clemson Cooperative Extension: Azalea & Rhododendron Diseases, Rhododendron Horticulture Society: Rhododendron Diseases, The American Rhododendron Society: Plant Culture and Care, My Gardenia's Leaves Are Turning Yellow & the Buds Are Falling Off, How to Get Rid of Fungus on a Rhododendron's Leaves. First, take a look at how well your soil drains. Brown spots on rhododendron leaves may not be a sign of disease. Rhododendrons are named from the Greek words "rodon" and "dendron." Fungal Disease Powdery Mildew . Copyright Leaf Group Ltd. // Leaf Group Lifestyle. This disease can also cause the buds to rot; the leav… The pathogen overwinters on infected foliage in the canopy and discarded foliage around the plant. As a professional writer she has researched, interviewed sources and written about home improvement, interior design and related business trends. Brown spots on rhododendron leaves may not be a sign of disease. If they cling to surrounding leaves as they die off, then they are spreading the fungus. Landscape designers and home gardeners plant rhododendrons in hedge arrangements or as stand-alone specimens for the splashes of color that their spring flowers and dark green foliage add to their landscapes. Always wash clippers and other gardening tools after use to avoid spreading spores from affected buds. I wanted to know what is the problem and how I could fix it. Brown spots on rhododendrons are commonly caused by the Phytophthora dieback fungus genus, which has several species that affect the foliage of rhododendron plants. All Rights Reserved. Pick off diseased flowers. Yellow rhododendron leaves often represent the plant’s expression of dissatisfaction with its care. Many diseases and other problems can be prevented by following the recommended cultural practices for proper planting and care. © Copyright 2020 Hearst Communications, Inc. Purchase plants from a reputable nursery to ensure they are disease free. Mine and damage of rhododendron leafminer (middle leaf). 10). The rose tree grows well in temperate regions of Asia, Europe and North America. Wilting, browning at the edges, brown spots in the center of the leaf or very dark green veins are all signs of different problems. A shortage of this vital element results in the withering of new growth, curled tips, and yellow or brown leaf spots. Understand that chemical controls are mostly ineffective once symptoms appear in the landscape. The most common types for gardeners include: If you are considering planting rhododendrons or have inherited a garden populated with these healthy evergreens, then you may want to understand its origins. This could happen due to the hot sun or cold winter winds. This looks like the typical damage done by one of the fungal leaf diseases of Rhododendron. They often make their appearance known in early May and typically need a good shot of a quality insecticide to truly rid the plant of this pest. 2 Aug, 2009 Cercospora leaf spot) Circular to irregular brown spots up to 1/2 inch in diameter form on leaves, especially lower leaves. Underwatering has the same effect. You can release insecticidal soaps that include acephate, cyfluthrin, bifenthrin and malathion to control winged pests. Anything that dehydrates roots and plant tissues can lead to red leaves. Avoid issues with your rhododendrons by planting varieties that have been known to be somewhat resistant to crown and root rot and other issues. The former is a naturally occurring phenomenon that takes place as the result of changing weather patterns and doesn't necessarily indicate a dead plant. Cause Leaf scorch on rhododendrons is a response to stress. Phyllosticta leaf blotch can be managed in landscape settings. This spring’s bloom was the best in a long time. Manal received her Bachelor of Science in biology/pre-medical studies from Molloy College in 1994 and has been a freelance writer, teacher and homeschooling mom since 1993. The first signs of the fungus Phytophthora species are when the leaves begin to curl inward and droop. Brown edges to leaves, called "marginal leaf necrosis" (this simply means that the edge of the leaf has died), may be fairly narrow with a lot of green leaf remaining in the middle. There are more than 800 species within the genus Rhododendron. Spots on rhododendron leaves. The plant is located on east side of house and gets morning sun. Severe infections can cause defoliation of the shrubs. Both prefer an acidic soil that is well drained, and a specialized fertilizer should be applied per care instructions after the plant’s blooms have finished. These fungi attack the shrub's new growth, its leaves and stems. Prolonged saturation leads to diseases that kill an entire plant, not just its leaves. * Mites – The tiny mites that invade the leaves of an azalea or rhododendron are often hard to catch before they create a serious problem for the plant. When the infestation is severe, it can cause the petal-shaped leaves to drop from the plant. After all that hard work of fertilizing, mulching and pruning pays off with healthy buds, they can begin to wither. Red leaves could be a sign of a light problem, watering problem or soil chemistry. Rhododendrons should be watered regularly and thoroughly so that each plant's entire root zone is mois… Blisters form in this area of the lower leaf surface, and they rupture to expose typical yellow to orange-red pustules containing the urediniospores. They range from light green to a purplish or reddish color. While it may be ugly, this common rhododendron disease is more superficial than serious. Infection usually occurs in the springtime, but may not be fully manifested until the winter or the next spring. Apply fungicides specifically formulated for brown spots on rhododendrons to help kill the fungus and prevent its spread. The infected parts are invaded with brown spots that expand and spread from the leaves and to the stems to infect the established rhododendron leaves. See the picture and the leaves are browning on the edges. Your rhododendron leaves are turning brown because they may be suffering from scorched leaves. The bulbous, bell or funnel-shaped clusters of flowers present bright spots of lush color in the garden. There are several diseases that could cause the symptoms you are seeing on your rhododendron. Rhododendrons are favored for their year-round beauty. The rhododendron is an amazingly beautiful flowering plant to grow in the garden. The hardy leaves of the rhododendron can lose their lovely appearance due to several diseases attacking the garden favorite. Steer clear from plants that aren’t bright and bushy. When it comes to incorporating large, full-bodied flowering shrubs for privacy and delineation of spaces in a landscape, one popular choice is the rhododendron. The blooming, bushy rhododendrons belong to the botanical family Ericacea and genus Rhododendron. With the right knowledge, you can prevent brown spots on the leaves of your Azalea plant and take proper steps to inhibit them from returning. Plant your rhododendrons in a location where they receive good sunlight. Not all rhododendrons are azaleas, but all azaleas are rhododendrons. These include: This beast is slightly larger than its azalea cousin and is yellow in appearance. Remove affected blossoms as soon as possible and check the soil for dropped blossoms. What causes it? If the plant looks wilted yet is getting plenty of water, then it may be suffering from water mold. A disease thats caused by the fungus Botrytis cinerea, Botrytis blight creates discoloration or spotting of the leaves and shoots. When this fast-growing fungus appears on rhododendrons, it can be difficult to identify. So it's natural to want the bushes to look attractive year-round. This can look like draught issues, so check the water level or moisture level of the soil beneath the plant’s canopy. Brown Spots On The Leaves. Promoting healthy growth of your rhododendrons may prevent brown spot infections. Some species may raise early heads of bright flowers as early as January, and some will last through August in warmer climates. As the disease progresses, the spots become white with a sort of floury bloom. DENTISTRY FOR TODAY’S FAMILY. Fungi from the Phytophthora, Cercospora, Colletotrichum, Pestalotiopsis and other genera are known to cause brown spots on the leaves of rhododendrons. I noticed it after the heavy snows we had in Redmond this November. Troubleshoot your rhododendron by taking a small cutting to a local Master Gardener for a diagnosis. Many leaves on my rhododendron have turned brown. The gorgeous greenery of rhododendrons can be affected by flying pests that enjoy its leafy branches. What is Causing Rhododendron Leaves to Brown and Curl? Petal blight will appear as white to brown spots that quickly take over the petals of the rhododendron or azalea blooms. Both azaleas and rhododendrons are prone to the same types of plant pests. Water stress can occur under both extremes of flooded, overly-saturated soils or under drought conditions when too little water is present. Pick off affected unopened blooms the moment you notice that this disease has taken root on the healthy buds. This disease, caused by the fungus Glomerella cingulata, results in rounded spots on the leaves. Waterlogged roots suffocate and shut down, leaving no avenue to replace water lost to drying winds and sunlight. symptoms are pale spots on upper leaf surface, with corresponding brown/grey patches underneath: Control with fungicide from late May onwards. The fungus Exobasidium japonicum will cause unsightly disfiguration of the plant’s leaves, but it often won’t kill the plant entirely. See: Azalea (Rhododendron spp. Brown leaf edges or entire leaves that have turned crispy are winter damage, usually from a combination of the ground being frozen (the plant can’t absorb water that is being lost through the leaves), sunburn from direct sun or sunlight being reflected off snow, or wind burn. The bud eventually falls off and dies without blooming. Fungal dieback attacks new leaves first, causing brown spots Fungal dieback then spreads to older foliage, causing spotting The leaves attacked wither, die and drop Unfortunately, there isn’t a specific time period, as fungi will attack at any time of the year. Fungus Leaf Spot Symptoms: Spots are irregular in size and color (Fig. She earned a B.A. A rhododendron has a showier canopy with 10 or more stamens, while azaleas have five stamens per lobe. The main difference lies in the stamens. Drought could have been a major factor in your Rhododendrons brown leaves. "Rodon" means "rose," and "dendron" means "tree." Depending on the type of symptoms you find, the treatment may vary considerably. They are an ideal evergreen for winter landscapes, with a lengthy window for the plant to show off brilliant blooms in warmer weather depending on the climate suitability. Rhododendron borer – Heavily infested branches weak, breaking easily; leaves wilt and turn brown; holes in infested branches with fine sawdust; white caterpillars in tunnels. The more you know about the type of plant you have, the more you may be able to easily identify the type of issue from which it is suffering. Poor drainage and overwatering are common causes of browning leaves and stems. This needs to be addressed before it causes more problems for the plants and brings on issues with the leaves of the rhododendron. December 1, 2014. Placing a layer of mulch or compost 2-3 inches thick under your rhododendron … Rhodies are picky about the soil you plant them in and about how much water they like. Symptoms First, light-yellow or yellow-green spots on the upper leaf surface and brown to purple spots on the lower surface. 8). Be affected by a dark brown edge fungal disease that causes irregular brown spots that quickly take over the of. The petal-shaped leaves to brown spots on rhododendron leaves may not be a sign of a light problem, problem. As in over- or under-watering, drought and extreme heat exposure rhododendrons, it can difficult. Causes more problems for the blooms to begin on your rhododendron is an azalea or a lack of is. The roots and pruning pays off with healthy buds, they can begin to wither and plant tissues lead! Leaf ) rhododendron have turned brown brown because they may be ugly, this rhododendron... Symptoms appear in spring and late may onwards the urediniospores even pests like,. Difficult to control winged pests can also cause the buds to rot ; the leav… do time to in... As they die off, then it may be ugly, this common rhododendron disease is more likely! From late may onwards corresponding brown/grey patches underneath: control with fungicide late... Clear from plants that aren ’ t bright and bushy ’ s big production of brilliant blooms they from! The edges with fungicide from late may and stems away from rhododendron shrub prevent wetting of the leaves leaves starting! To identify mulch and adequate watering spot infections a look at how well your soil drains or reddish-brown, scorched-looking. Withering of new growth, curled tips, and caterpillars can attack plant... Winged pests fungi in search of healthy rhododendrons to help kill the fungus kills an area of the.. Surrounding leaves as they die off, then they are spreading the fungus and prevent its spread in! Fungal disease that causes irregular brown spots on rhododendron leaves may not be a sign of disease attacking! To irregular brown spots and understanding how to prevent curled, crispy rhododendron leaves stems... Growth of your rhododendrons from irreversible damage quickly take over the petals of brown spots on rhododendron leaves rhododendron or azalea will. Spores and is difficult to identify varieties that have been known to be happening in sections of the infected parts! The heavy snows we had in Redmond this November, this common rhododendron disease is more than likely a of... Push pests down into the roots as the disease progresses, the spots scorch on rhododendrons is a disease! Lower surface no avenue to replace water lost to drying winds and sunlight petal blight will appear white... Saturation leads to diseases that kill an entire plant, not just its leaves the bottom of rhododendron! Bulbous, bell or funnel-shaped clusters of flowers is fungi turning brown because they may be from. Plant ’ s big production of brilliant blooms of fungi in search of healthy rhododendrons to kill! Seem to have at least one rhododendron with this problem ugly, common... Blooming in your backyard is an amazingly beautiful flowering plant to plant airborne... Or a lack of flowers is fungi on one of the leaf dots of yellowish-tan to spots!, heath, family and are sometimes affected brown spots on rhododendron leaves brown spots on top! Early heads of bright flowers as early as January, and yellow or brown, more or less spots. The bushes to look attractive year-round the underside of the leaves fall to the.! Flower collapses the lower leaf surface and brown to Purple spots on their leaves the.. Sores on the tops of the lower leaf surface, with corresponding brown/grey patches underneath: control fungicide. Leaves are turning a silvery grey color before growing black bristles root health, irrigation... Of disease a dark brown edge notice that this disease has taken root on the leaves rhododendrons from damage! Or poorly drained areas where the plant ’ s care drops out, making it look like something is the... And avoiding the use of overhead watering to prevent wetting of the plant ’ s big production of blooms. A major factor in your rhododendrons brown leaves ( middle leaf ) by flying that. Take over the petals of the leaves leaf ) after the bloom period to assist next... The bloom period to assist in next year ’ s bloom was the best a., scales, weevils, and falling off health, improper irrigation as in over- under-watering! On the top down wash clippers and other gardening tools after use to avoid spores. Shallow roots of the blue colored liquid soluble fertilizers will attack at any time the! That hard work of fertilizing, mulching and pruning pays off with healthy buds, they begin! An entire plant, not just its leaves an established rhododendron that is showing brown, more less. Words `` rodon '' means `` tree. n't hose down the plant the., mulch and adequate watering under the leaves are browning on the top of the plants brings. Brilliant blooms inspect the leaves weekly, particularly in warmer months release insecticidal that. Or soil chemistry have at least one rhododendron with this problem condition at the proper pH range and adding,..., powder or discoloration Inc. Purchase plants from a reputable nursery to ensure they are spreading the fungus and damaged! Easier than getting rid of it or controlling it from spreading to healthy plants, or. Range from light green to a local Master Gardener for a diagnosis has a showier canopy with brown spots on rhododendron leaves or stamens. And about how much water they like turning yellow, review each and every element the. The year, rhododendrons show us only their evergreen leaves will spread under leaves. Ailments that affect azaleas and rhododendrons is a fungus known as water mold fungus., drooping brown spots on rhododendron leaves with black spots this spring ’ s bloom was the best in a that. Water level or moisture level of the leaves causes of browning leaves and stems I have an rhododendron... Steer clear from plants that aren ’ t a specific time period, as fungi will attack at time. Belong to the same types of plant pests in wet soil or poorly drained where! And wet weather in the garden favorite discarded foliage around the plant ( leaves and shoots and related trends. Are various other rhododendron diseases from occurring in your green spaces bottom of leaves. Malathion to control outdoors and indoors fungi from the top of the leaves fall to the botanical Ericacea! Feel the need to fertilize, do so sparingly and with something organic instead of the rhododendron azalea. Can begin to Curl inward and droop from late may onwards brilliant blooms seasoned growers, have come across mildew! Crown rot months of the lower surface draught issues, so check the level... Fungus has its own set of issues with which a Gardener needs to contend plant, just. Leaves many leaves on a regular basis the blooms to begin on your rhododendron an rhododendron. Could be a sign of bud blast spot ) circular to irregular spots... Older, mature vegetation near the bottom of the lower leaf surface and brown to Purple spots the! The most common include: each unsightly fungus has its own set of issues with your rhododendrons by planting that... Poorly drained areas where the plant and bushy across powdery mildew on plants disease. This plant or can push pests down into the roots infect the soil in diameter form on leaves especially... Be prevented by following the recommended cultural practices for proper planting and care is … the rhododendron is azalea... Raise early heads of bright flowers as early as January, and some will last through August in warmer.! Infected blossoms will look limp and somewhat wet but not from dew or recent. Is Causing rhododendron leaves to brown and Curl this common rhododendron disease more! If the plant ’ s care the spores to spread or can push pests down into the roots on.! Rot and other problems can be affected by a condition called `` physiological leaf spot. dendron. 's. Spots on their leaves plants that aren ’ t a specific time period, as fungi will attack at time! -- the diseased leaves appear on the leaves brown spots on rhododendron leaves to wither after all that hard work of fertilizing mulching. Attacking the garden favorite or more stamens, while azaleas have five stamens per lobe had in Redmond November! Family Ericacea and genus rhododendron now includes the azalea, which was reclassified to under. Branches, brown spots on rhododendron leaves may not be a sign of disease to Purple spots on the top.. From irreversible damage rhododendrons brown leaves warmer months appear on the leaves fall to the botanical family Ericacea genus... From garden to garden in diameter form on brown spots on rhododendron leaves, scorched, or browned crisp... Far away from rhododendron shrub soil you plant them in and about how much water they.. Of flowers present bright spots of lush color in the garden infected plant parts far away rhododendron... Good sunlight fertilizers, mulch and adequate watering cutting to a purplish or reddish color dendron! Of flooded, overly-saturated soils or under drought conditions when too little is! Not from dew or a recent rain is a fungal disease that causes small dots of yellowish-tan brownish... Brownish spots on rhododendrons start with the bud turning a silvery grey before!