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?

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

Blackened leaves on purple sage in Utopia TX
December 08, 2010 - I live in Utopia Texas and have a 5-ft. Texas Purple Sage that has developed a black appearance on the leaves. What is this and what can I do about it?
view the full question and answer

Live oak leaves yellowing from Denton TX
January 26, 2012 - In autumn of 2010 I planted 10 live oaks about 6 to 7 ft. tall. I have see that during the month of Dec. 2011 to Jan. 2012 they are showing some yellow leaves. What can I do to help them?
view the full question and answer

Dying branches on Texas Mountain Laurel from Kempner TX
September 14, 2012 - The branches on my Texas Mountain Laurel are very dry and brittle. The leaves are also starting to die. The tree has been in my yard for six years and prior to that it sat wrapped in burlap for ov...
view the full question and answer

Bloom color change in Choctaw Crape Myrtle
July 30, 2007 - In 2006 my wife bought a Choctaw Crape Myrtle from a local nursery. It had a tag from Greenleaf Nursery and had several blooms in the "correct" pink color. The plant was 5-6 ft tall. It has grown...
view the full question and answer

Problems with Green Cloud cenizo in Tucson, AZ
June 15, 2009 - I have a large number of Green Cloud Texas Rangers on my property. I water all very consistently, once a week and most of these are around 5-6 ft tall and 15 years or more old. We've only had a few i...
view the full question and answer

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