• Enter your email address to follow this blog and receive notifications of new posts by email.

  • Upcoming events in Middle Tennessee

     

    Save the Date: Perennial Plant Society’s 30th Plant Sale is April 4, 2020, 9 a.m. – 1 p.m. at the new Expo 3 Building at The Fairgrounds Nashville. Here’s where you can find the newest varieties of perennials, shrubs, vines and annuals from local growers, along with long-time, never-fail favorites, ready for spring planting. Learn more at the PPS website.

     

  • Categories

  • Archives

Keep zinnias free of powdery mildew

QUESTION: I love zinnias and plant them every year. Sometimes they do well and look great all summer, but many years the leaves are covered in powdery mildew. How do you get rid of this problem?

Powdery mildew is a fungus that appears as gray or white splotches on leaves, stems and flowers of zinnias and other ornamentals and some vegetable plants. It travels by airborne spores, and thrives when nights are moderately cool and foliage stays damp. A mild covering of powdery mildew is merely unattractive, but a severe case can cause distorted shoots and leaves, misshapen flowers, or can prevent flowering altogether.

The best defense is to grow zinnias in full sun, since hot temperatures inhibit the growth of mildew. Don’t allow them to get too crowded; you want air to circulate freely around the plants. Water only in the morning so foliage has time to dry before nightfall.

I always try to suggest the good-cultural-practices methods first for problem-solving, but there are also fungicides available that can deter powdery mildew. If you choose that route, apply fungicide as soon as you begin to spot the mildew. The University of Tennessee Extension has a short list of products in a publication about powdery mildew here. Be sure to read and follow directions on the product label.

Zinnias are not the only garden favorites plagued by powdery mildew. Lilacs, roses, crepe myrtles and other woody ornamentals, and many herbaceous ornamentals and bedding plants are also targets when weather conditions favor the fungus.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: