Rent Shop Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Monday - October 13, 2008

From: Clarendon Hills, IL
Region: Midwest
Topic: Diseases and Disorders, Herbs/Forbs
Title: Mildew in Phlox paniculata
Answered by: Barbara Medford

QUESTION:

I planted garden phlox (phlox paniculata) in my front landscaping and it is suffering from mildew. It is wet on that side due to a down spout and it may benefit from being split. Does anyone know of a treatment to eliminate the mold? They really do not flower well.

ANSWER:

Your native Phlox paniculata (fall phlox) is probably not in any danger from the mildew, although it does make the plants somewhat unattractive. Mildew is common in the Fall, because of cool nights and still-warm days. Too much water in a flower bed, such as from a downspout, can cause other problems in plants, like root rot. You might want to consider finding a way to channel the outflow from your downspout away from the flower bed. Since your phlox is a perennial, you might also consider dividing it and moving it to another area. The best preventions of mildew are good air circulation and sunshine. Since it isn't always possible to provide those, read this article from About.com Organic Gardening on   Preventing and Controlling Powdery Mildew. One tip we picked up from this and other sources, which surprised us, is that one of the best treatments for powdery mildew is a good spray of water on the affected plants. It should be done early in the day, so that the water will have plenty of time to dry before sundown, but it does seem to work. You could go on to try the baking soda spray solution mentioned in the article, although we have heard mixed reports on the efficacy of that method. There are fungicides available, but that is likely overkill for this problem. Rake up the fallen leaves and blooms, and keep the area clean, so mildew can't winter over.


Phlox paniculata

 

 

 

More Diseases and Disorders Questions

Fasciated Texas mountain laurel
November 05, 2013 - I've noticed some strange things hanging off some of the purple mountain laurels in my area. They hang low, and look almost like large, dangling trumpet flowers, but are flat, and have little bumps o...
view the full question and answer

Mountain laurel with fasciation
July 24, 2014 - My Texas Mountain Laurel bush has developed several "crested branches." What causes this, is it harmful & how do I get rid of them??? Thank you!
view the full question and answer

Need help controling suckers from an ornamental plum in San Pedro, CA.
August 10, 2010 - I have an ornamental plum tree in my garden which produces a lot of suckers in my vegetable beds. I do not want to use harmful chemicals and cutting them back is a hopeless venture and leaves small...
view the full question and answer

Yellow-orange fungus on Ash tree in Ohio
July 14, 2009 - Dear Mr. Smarty Plants, I have a large ash tree which started growing some yellowish orange fungus around the base this spring. With this fungus there are also black bugs with a orange marking near i...
view the full question and answer

New Jersey Tea shrub wilting and losing leaves
December 30, 2013 - I have New Jersey Tea shrubs transplanted last spring from nursery stock (18 tall, grown local) I live in SE WI. They are planted in part shade. There has been 6" of snow on the ground for weeks now...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.