En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Monday - March 28, 2005

From: SF, CA
Region: California
Topic: Diseases and Disorders
Title: Pustules on geranium
Answered by: Joe Marcus

QUESTION:

I have a geranium that has developed oblong red/brown pustules/raised bumps on the undersides of the lower leaves. The foliage around the bumps is stil green but everything else has yellowed

ANSWER:

Thank you for writing! The problem you describe sounds like oedema (sometimes spelled: edema; pronounced: ed-ee'-ma). Oedema is not a disease, but a physiological disorder. It is a problem with many plants, but is an absolute disaster for geraniums (Pelargonium X hortorum) -- especially ivy geraniums (P. peltatum). Native geraniums are not as affected by the condition. Oedema is a result of ruptured cells, usually on the underside of a leaf, caused by a complex of issues involving water availability, humidity, temperature, air movement, and plant nutrient levels. In severe cases, the plant will drop the injured foliage, sometimes denuding the plant. The University of Georgia Cooperative Extension website has a nice article on Geranium Diseases including a section on oedema.
 

More Diseases and Disorders Questions

Oaks at Wildflower Center from Wimberley TX
September 05, 2012 - I know you have numerous Quercus fusiformis examples at the ladybird Johnson Wildflower Center. My question is, do you also have Quercus virginiana growing there? Also, is Oak Wilt a disease that ...
view the full question and answer

Shasta Daisies without Petals
August 21, 2014 - My shasta daisies do not have the white petals, only the yellow center is in bloom. There are no visible signs of insects. They get a good amount of sun - about 5 hours per day. What could be the prob...
view the full question and answer

Is post oak resistant to oak wilt from Dallas TX
November 22, 2013 - I am confused. The NPIN website says that Post Oak IS susceptible to oak wilt, but all the other information I have been able to find says that it is resistant to oak wilt and rarely gets the diesase....
view the full question and answer

Control of sooty mold from aphids in Crape Myrtle
February 25, 2007 - I have a crape myrtle in my front flower bed that has a sooty black substance on the leaves and trunk. I've done research and understand this is caused by aphids. My question is how do I get the bl...
view the full question and answer

Suffering Yaupon in Austin
July 14, 2012 - I am in the Austin area and I planted a Pride of Houston Yaupon in my back yard in March. It is in full sun. Lately the leaves have been turning pale green and now they fall off the tree upon touchi...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center