Cooler weather leads to disease issues on plants


Rain and cooler temperatures have not been kind to some of our plants, especially my peonies.

Recent rains combined with the cool temperatures have been the perfect environmental conditions for many diseases to flare up in our gardens and landscapes.

My peonies and many others’ have been affected by botrytis blight, which is not surprising with this weather.

This disease usually starts in the early part of the season, just as the peonies emerge from the ground. However, this year, plants weren’t affected until this recent cool wet period.

Botrytis blight loves cool, cloudy and overcast, and moist conditions to thrive. It not only affects peonies but lilies, annuals and other ornamental flowering plants.

I suspect that you have seen this before on your annuals, particularly petunias and geraniums. The flowers begin to mold and develop a mass of gray fuzzy fungal spores.

When the weather conditions warm up and we get sunshine, the disease development ceases.

However, on the peonies, the infection has already occurred and you will likely see large, brownish irregularly-shaped spots on the leaves. The flower buds may never have opened, and if they did, they might have blackish spots or moldy petals.

You may see the fuzzy fungal spores after a rain on the petals or leaves.

The problem is the weather. Fungicides sometimes may control the disease but the timing of application is extremely challenging.

If your peonies look like this now, good sanitation is helpful to decrease the amount of spores hanging around to affect next year’s growth.

Remove any diseased flower buds as well as foliage. If plants are in the shade, try to thin trees to expose them to better sun that encourages drying of the foliage. If they are crowded in the garden, try to open up the area around them as well.

In the fall, cut the plants back and destroy the foliage. Don’t compost and reuse in the perennial garden.

If this disease occurs every year, you should consider replanting them to an area where they have lots of space and full sun.

Botrytis blight also affects Asiatic lilies and can prevent blooms from looking spectacular. My Asiatic lilies are just beginning to bloom and the ones in full sun that have good air circulation are perfect.

However, those in the side garden that are surrounded by thick daffodil foliage that remains green are affected by botrytis blight.

This is a perfect example of the need for better air circulation needed to dry the foliage. I keep saying I need to replant the daffodils but haven’t gotten around to doing this yet. Maybe next year.

The bottom line for some of these weather-induced diseases on annuals and perennials may be to wait for nice warm weather. Clean off any diseased foliage, even if it means cutting the plant back to the ground (perennials) and trimming annuals.



Reader Comments ...


Next Up in Home Garden

CHEERS! The Dayton Art Institute Oktoberfest mugs are a coveted collectible
CHEERS! The Dayton Art Institute Oktoberfest mugs are a coveted collectible

Handcrafted mugs created by regional potters have been a sought-after collectible since Oktoberfest at the Dayton Art Institute began in the 1970s.  The earliest mug in the DAI’s collection, from 1974, is made from glass and features a printed DAI logo. In the years following the mugs were mass produced until the idea to use local potters...
What cats see when they look in the mirror
What cats see when they look in the mirror

Mirror, mirror on the wall, who’s the fairest of them all? Abby, our 16-year old cat, thinks she is. When Abby could no longer jump up on the kitchen counter to eat from her bowl, we searched for a place she could easily reach but Teddy, our Lab, could not. We placed the queen bee’s bowl in front of a large mirror on the master bathroom&rsquo...
Are household disinfectants making kids overweight? Study finds possible link
Are household disinfectants making kids overweight? Study finds possible link

Obesity affects nearly 1 in 6 children in the United States, according to new data from the Robert Wood Johnson Foundation’s State of Obesity report. And new findings from the Canadian Medical Association Journal reveal there may be more contributing to that stat than overeating. Overweight children are approximately five times more...
Seven-Day Menu Planner
Seven-Day Menu Planner

9/23 Family Sunday Enjoy family day with your own Roast Chicken (5 to 7 pounds), mashed potatoes, gravy, peas with pearl onions (from frozen) and mixed greens. For dessert, drizzle creme fraiche or half-and-half over bread pudding. Plan ahead: Save...
Chrissy Teigen says we've been mispronouncing her name this whole time
Chrissy Teigen says we've been mispronouncing her name this whole time

You've probably been pronouncing Chrissy Teigen's last name wrong. We're just as shocked as you are. In a video posted on Teigen's Twitter last night, she dropped the wild news: "I'm tired of living this lie: it's 'Tie-gen,' " she says. "Isn't it, Mom?"          ...
More Stories