Explore Plants

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
    
 

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

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

Esperanza with rust spots in Corpus Christi, TX
November 30, 2009 - I have a young esperanza plant and the leaves have what looks like rust spots all over them. What is the cause of this and what can I do for it? My other larger and older esperanza does not have this....
view the full question and answer

Ruffly foliage on native lantana
November 05, 2013 - A native lantana in my front yard has developed ruffly foliage on one stem. It looks like miniature broccoli. What can this be?
view the full question and answer

Problems with Juniperus ashei in San Antonio
May 27, 2011 - I live in San Antonio and have many juniper trees. On inspection I do not see insects or any other form of damage, but my trees are turning brown and dying. I have already had to cut one down. When...
view the full question and answer

Oak trees shedding leaves in Denton TX
May 27, 2012 - In Denton, TX we have two mature Quercus buckleyi. It is May 11th 2012 and one of these trees has been shedding green leaves for the last week. The only changes we have made are: planted English ivy...
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.