Bulbs Flower Basics Flower Beds & Specialty Gardens Flower Garden Garden Furniture Garden Gnomes Garden Seeds Garden Sheds Garden Statues Garden Tools & Supplies Gardening Basics Green & Organic Groundcovers & Vines Growing Annuals Growing Basil Growing Beans Growing Berries Growing Blueberries Growing Cactus Growing Corn Growing Cotton Growing Edibles Growing Flowers Growing Garlic Growing Grapes Growing Grass Growing Herbs Growing Jasmine Growing Mint Growing Mushrooms Orchids Growing Peanuts Growing Perennials Growing Plants Growing Rosemary Growing Roses Growing Strawberries Growing Sunflowers Growing Thyme Growing Tomatoes Growing Tulips Growing Vegetables Herb Basics Herb Garden Indoor Growing Landscaping Basics Landscaping Patios Landscaping Plants Landscaping Shrubs Landscaping Trees Landscaping Walks & Pathways Lawn Basics Lawn Maintenance Lawn Mowers Lawn Ornaments Lawn Planting Lawn Tools Outdoor Growing Overall Landscape Planning Pests, Weeds & Problems Plant Basics Rock Garden Rose Garden Shrubs Soil Specialty Gardens Trees Vegetable Garden Yard Maintenance

Why Are My Rhododendron Leaves Turning Brown?

How to Start Lemon Seeds Indoors - watch on youtube
Why Are My Rhododendron Leaves Turning Brown?

Why Are My Rhododendron Leaves Turning Brown?. Rhododendrons are a shrub in the Ericaceae family, which also includes mountain laurels and blueberries. Over a thousand species are contained within the Rhododendron genus, but most have enough points in common that the same general care can be used for all species. Leaf discoloration can be caused by...

Rhododendrons are a shrub in the Ericaceae family, which also includes mountain laurels and blueberries. Over a thousand species are contained within the Rhododendron genus, but most have enough points in common that the same general care can be used for all species. Leaf discoloration can be caused by a handful of factors, but it is relatively simple to treat.
Natural Spots
Not all rhododendrons are the same. Certain cultivars, or strains, have inherently spotted leaves even when perfectly healthy. These spots are a faint purple, not rusty red or dull brown like spots due to disease. You can expect to see these spots on "Blue Ensign" and "Mrs. G. W. Leak," among others. Familiarizing yourself with your new rhododendron will help you identify diseases and trouble spots later.
Fungi and Viruses
Botryis, pestalotia, phyllosticta, and septoria are all species of fungus that can give rhododendron unsightly brown spots, weakening a plant and lowering its photosynthesis efficiency if allowed to go unchecked. Necrotic ring spot is a virus evidenced by reddish-brown rings or spots on the leaves. There actually isn't much known about it, but because it doesn't spread from one shrub to another or damage the plant in any other way, it's not considered serious.
Physical Damage
Direct damage to the leaves can be caused by multiple factors, including frostbite in winter (although the full measure of the damage may not show up until April), sunburn in summer (rhododendrons are not ideal for long hours of direct sunlight), chemical contact or a lack of water. Not only can physical damage to the leaves brown them, but it also increases the likelihood that the affected leaf will be further compromised by fungal or viral infection. Chemical drift from cleaners or paint can stress the plant in ways that may not show up for weeks or months, so it's wise to clean or paint on calm days.
Non-Chemical Treatment
Whether you suspect the leaves are discolored due to infection or because of some other cause, remove the spotted leaves in order to prevent the shrub wasting resources on already damaged leaves; they are unlikely to turn back to green. If a fungal infection is the culprit, move a potted rhododendron to a location with better air circulation to prevent further spores from settling on the leaves, if feasible.
Fungicide
Rhododendrons are hardy enough that organic or nonchemical treatment is usually sufficient to solve the problem. But occasionally further steps may be necessary. If you are fairly certain a fungal infection is present, a fungicide can be used without harming the rest of the plant. All other causes of leaf discoloration may be treated safely without chemicals by removing the affected leaves.

Check out these related posts