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

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

QUESTION:

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?

ANSWER:

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 Diseases and Disorders Questions

Overwatering and fertilization of whiteleaf manzanita
July 27, 2007 - Hi, I have an Arctostaphylos Dr. Hurd, southern California coast, several years old, 10 feet, that has a few large branches with yellowing and spotted leaves... also dropping many. causes? remedy? sh...
view the full question and answer

Why are large numbers of leaves falling from my Live Oak trees in Driftwood, TX?
June 24, 2015 - Today is June 6, 2015 and I have noticed that for the last week and a half, only a few live oaks out of many, have been losing large numbers of green leaves and turning brown on the ground. I cannot ...
view the full question and answer

Wilting American Smoke Tree in Texas
April 21, 2013 - I planted a young American smoke tree last fall (mid-November) and it put out a good show of tentative new leaves this spring. Then to keep the tree form I clipped some little shrubby start ups at the...
view the full question and answer

Live oak leaves turning yellow after planting in Houston
December 19, 2011 - We bought a 65 gallon live oak in early October, and have been watering fairly heavily three days a week. It seemed OK, then all of a sudden lots of the leaves are turning yellow. Is it getting too ...
view the full question and answer

Ring of small holes around pecan tree branches
May 05, 2009 - I live outside Cooper, TX and I have a pecan tree about 15 years old, which I just noticed has little round holes (about the size of a pencil) going around the branches. It branches out about 3 feet ...
view the full question and answer

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