En Español

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?


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

Thursday - May 29, 2008

From: Austin, TX
Region: Mid-Atlantic
Topic: Diseases and Disorders, Herbs/Forbs
Title: Possible mildew on standing cypress
Answered by: Barbara Medford


My mother-in-law took some standing cypress seeds from Texas to Virginia several years ago. They have always done very well, but this year they are growing very tall, but the bottom half of the stalk is turning silver. They have had 7 inches of rain recently. Is this a mildew? What can she use on it that won't hurt the hummingbirds?


Ipomopsis rubra (standing-cypress) is native to both Texas and Virginia, so there is certainly no reason why it shouldn't do well in your mother-in-law's garden. Your description sounds like there could be a mildew problem. Read this article from Ohio State University Extension on Powdery Mildew on Ornamental Plants. One point the article makes is that mildew is rarely that dangerous a disease on ornamentals, and that powdery mildew fungi produce airborne spores and infect plants when temperatures are moderate (60 to 80 deg) and will not be present during the hottest days of summer. With any pest or disease, cultural controls are far better for the environment (including the hummingbirds) than chemical controls, which should be a last resort. Cultural controls for this plant would include making sure it is in full sun, not shaded, that it is not watered from above (of course, that's what rain does), and that the plants are far enough apart for good air circulation. As this plant is a biennial, it will seed itself at the end of the season, and the gardener should be sure to keep the seedlings thinned out as they come up.

You are probably correct that 7 inches of rain has not helped the situation. However, drier, hotter air is coming with the onset of summer, and the problem may resolve itself, or at least not damage the plants or limit the flowering. Standing Cypress can get quite tall, up to 6 or 7 feet, so it's worth taking the trouble over it. In the above link, you will find recommendations for chemical controls but, as said before, we much prefer the cultural practices that promote a healthy plant. Since we don't know what county in Virginia your mother-in-law lives, we can't give you a specific link to her county extension office. However, she can find them under "County Offices" or simply search on her county name and "extension office." That would be a far better source for recommendations on treatment of the mildew than anything we can offer from here.

Ipomopsis rubra

Ipomopsis rubra

Ipomopsis rubra

Ipomopsis rubra



More Herbs/Forbs Questions

Needs Help with Peonies
January 14, 2011 - With the clay soil in North Texas (Frisco) which variety of peony would thrive and become a reliable bloomer? I do work on amending the soil with expanded shell and compost, but ultimately, we still h...
view the full question and answer

Standing cypress turning brown in San Antonio
June 12, 2011 - Last year I bought and planted a standing cypress. This year several plants came up. The tallest one was about 1 foot tall. After blooming the plant began to turn brown and die. My question: Is t...
view the full question and answer

Which plants are resistant to dog urine in Ashmore, IL??
May 21, 2012 - Which native plants are resistant to dogs urinating on them?
view the full question and answer

Kinnikinnick for a green roof
July 04, 2012 - Hi Mr. Smarty Plants, I live just north of Seattle and want to build a green roof (outdoor kitchen) I'm concerned about the weight of the soil (saturated), drainage etc. am building from scratch and...
view the full question and answer

Green blooms on Cedar Sage in Lucas TX
September 22, 2010 - I have two Cedar Sage (Salvia roemeriana) one purchased from your plant sale and one from a local nursery planted in part shade in the Dallas area. They seem to be quite happy and are blooming but ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center