Sacramento Digs Gardening Article
Your resource for Sacramento-area gardening news, tips and events

Articles Recipe Index Keyword Index Calendar Twitter Facebook Instagram About Us Contact Us

Weird weather brings botrytis outbreak

Sacramento Digs Gardening
BY Debbie Arrington PUBLISHED MAY 12, 2020

This poor Pink Promise hybrid tea rose was turned into a brown mess by botrytis. (Photo: Debbie Arrington)

Fungal disease loves cool, cloudy, moist conditions

“What is this and how can I fix it?”

That question came attached to a photo of what should have been a big beautiful red rose. Instead, each petal was deeply edged in brown.

In the days ahead, more Sacramento roses will seem to stop opening in mid-bloom and suddenly become covered with spots and brown patches. If left on the bush, these flowers turn to yucky gray mush.

It’s an early outbreak of botrytis, a common fungus that attacks a broad range of ornamental and edible plants.

Usually, local gardeners don’t see Botrytis cinerea on their roses until October or November. But recent weather conditions have been just right for this opportunistic pathogen. Botrytis loves temperatures in the 70s, cloudy afternoons and a little rain.

It’s that splash of moisture that really launched this attack – both in April and now in May. Botrytis needs moisture for growth in plant tissues and what it loves are tender flower petals. It can’t seem to resist a wet bud on a cool, cloudy day.

Nicknamed gray mold, botrytis will eventually overwhelm the flower and turn it into soft mush. The earliest stages look like pink measles or brownish water spots on light colored flowers. Those brown spots quickly grow until they consume the whole petal. The fungus grows so fast, the flower never fully opens.

Although botrytis is common in the fall, a spring attack seems worse because we have more flowers in the garden.

Besides roses, botrytis also attacks African violet, asters, begonia, carnation, chrysanthemum, cyclamen, cymbidium, gerbera, geranium, gladiolus, hydrangea, marigolds, orchids, petunia, poinsettia, primrose, ranunculus, snapdragon, zinnia and many other garden favorites.

According to UC Integrated Pest Management program, the best control of botrytis is “good sanitation.” Clip off infected blooms, put them in a plastic bag and dispose in the trash. Do not compost them; that just recycles the spores back into the garden.

Pick up fallen blooms and petals around the bush and dispose of them, too.

When the heat returns (which will be soon), botrytis will disappear – it can’t stand temperatures over 90 degrees. But expect it to come back again in October – especially after the first fall rain.

For more information on botrytis, check out these pest notes from UC IPM: http://ipm.ucanr.edu/PMG/r280100511.html

Comments

0 comments have been posted.

GENERAL GARDENING

An article about gardening.

Keywords:

gardening Sacramento integrated pest management roses botrytis pathogens disease control UC IPM plant diseases

Newsletter Subscription

Sacramento Digs Gardening to your inbox.

Taste Fall! E-cookbook

Find our fall recipes here!

Thanks to Our Sponsor!

Local News

Sites We Like

Garden Checklist for week of Nov. 3

November still offers good weather for fall planting:

* If you haven't already, it's time to clean up the remains of summer. Pull faded annuals and vegetables. Prune dead or broken branches from trees.

* Now is the best time to plant most trees and shrubs. This gives them plenty of time for root development before spring growth. They also benefit from fall and winter rains.

* Set out cool-weather annuals such as pansies and snapdragons.

* Lettuce, cabbage and broccoli also can be planted now.

* Plant garlic and onions.

* Keep planting bulbs to spread out your spring bloom. Some possible suggestions: daffodils, crocuses, hyacinths, tulips, anemones and scillas.

* This is also a good time to seed wildflowers and plant such spring bloomers as sweet pea, sweet alyssum and bachelor buttons.

* Rake and compost leaves, but dispose of any diseased plant material. For example, if peach and nectarine trees showed signs of leaf curl this year, clean up under trees and dispose of those leaves instead of composting.

* Save dry stalks and seedpods from poppies and coneflowers for fall bouquets and holiday decorating.

* For holiday blooms indoors, plant paperwhite narcissus bulbs now. Fill a shallow bowl or dish with 2 inches of rocks or pebbles. Place bulbs in the dish with the root end nestled in the rocks. Add water until it just touches the bottom of the bulbs. Place the dish in a sunny window. Add water as needed.

* Give your azaleas, gardenias and camellias a boost with chelated iron.

* For larger blooms, pinch off some camellia buds.

* Prune non-flowering trees and shrubs while dormant.

* To help prevent leaf curl, apply a copper fungicide spray to peach and nectarine trees after they lose their leaves this month. Leaf curl, which shows up in the spring, is caused by a fungus that winters as spores on the limbs and around the tree in fallen leaves. Sprays are most effective now.

Taste Spring! E-cookbook

Find our spring recipes here!

Taste Summer! E-cookbook

Find our summer recipes here!

Taste Winter! E-cookbook

Find our winter recipes here!