Host an Event Volunteer Join Tickets

Support the plant database you love!

DONATE TODAY

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 - 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

Anacacho orchid not leafing out in Georgetown TX
April 18, 2013 - February 2012 I planted 2 4-ft anacacho orchids which did well. This spring, they have yet to leaf out or even bud. There is green, however, when I scratch the stems and some suckers at the bottom of ...
view the full question and answer

Need help for diseased Cherry Laurel tree in Houston
October 19, 2015 - A couple of weeks ago the leaves on my decade old cherry laurel began to turn brown. Now they are entirely brown. I have not changed the way in which I cared for it, but about three days ago I noticed...
view the full question and answer

Loss of leaves from globe willows in Utah
July 26, 2008 - I have four globe willows that have been in my back yard for the past 6 years. For the past month they have been losing their leaves from the bottom up. We had aphids in some of our other trees and ...
view the full question and answer

Dying non-native St. Augustine grass from Austin
May 02, 2013 - Although we all know St. Augustine grass is not a good thing, I am stuck with it and am trying to save areas that appear to have take-all fungus. I have done much reading online and have tried peat m...
view the full question and answer

Rust spots on non-native red tip photinia
July 10, 2008 - I live in Oklahoma and my red tips have rust spots on leaves and some plants are losing leaves. This is a clay soil; can you give me any info. on how to solve this problem?
view the full question and answer

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