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
How to Get Rid of Mold on Hydrangeas
How to Get Rid of Mold on Hydrangeas. When conditions are warm and humid, several fungi can attack hydrangea shrubs, causing leaf spots and killing the flowers. Powdery mildew, for instance, covers the bottom sides of the foliage with gray mold. Not even well-protected greenhouse hydrangeas are safe. Gray mold or Botrytis blight has found a way of...
When conditions are warm and humid, several fungi can attack hydrangea shrubs, causing leaf spots and killing the flowers. Powdery mildew, for instance, covers the bottom sides of the foliage with gray mold. Not even well-protected greenhouse hydrangeas are safe. Gray mold or Botrytis blight has found a way of sneaking into the plant's sheltered environment. It targets the shrub's flowers. How you plant and maintain hydrangeas play a role in how susceptible to mold they are.
Things You'll Need
Fans
Fungicide
2 percent copper naphthalene
Shears
Rake
Ask the nursery staff what the spacing requirement is for your species of hydrangea. Plant accordingly to provide the shrub adequate air circulation, which creates an inhospitable environment for powdery mildew. Keep fans running if your hydrangea is indoors or in a greenhouse.
Treat powdery mildew at the first sight of spores on the hydrangea leaves, using a fungicide. Look for a thin layer of gray mold. Fungicides containing the chemicals azoxystrobin, fenarimol, paraffinic oil or thiophanate-methyl are labeled for controlling powdery mildew. Follow the manufacturer's instructions for application rate and frequency.
Disinfect greenhouse wooden surfaces with 2 percent copper naphthalene to kill Botrytis, the cause of gray mold in hydrangea flowers. Cover those surfaces with plastic to prevent ultraviolet rays from activating the spores.
Apply a fungicide containing iprodione, mancozeb or thiophanate-methyl before any signs of gray mold appear. Follow the manufacturer's instructions for the application rate. Spray the hydrangeas every one to two weeks on cloudy or rainy days.
Prune all infected plant parts and discard them in the trash can immediately to avoid transferring the powdery mildew and gray mold fungal spores to healthy tissue. Rake up any debris on the ground near the plant.
