Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Yellowing leaves on Mexican Plum in Salado, TX.
July 24, 2013 - I do live in Cental Texas (Salado) and I have the same problem with my Mexican Plum as the lady in Bellaire, TX. Mine was planted in June in a raised bed and receives sun all day long. Within the la...
view the full question and answer

Smarty Plants on mockoranges
May 25, 2005 - I live in Colorado where it is common to have 1 or 2 late frosts. I planted 4 littleleaf mockoranges (Philadelphus Microphyllus) 2 years ago and they are pretty much in full sun most of the day. I h...
view the full question and answer

When is the best time to trim oak trees in Driftwood TX?
September 09, 2010 - When is the best time to trim oak trees?
view the full question and answer

Young Bur Oak not Flourishing in Texas
November 06, 2014 - We have a bur oak in our SW Travis County lawn in Texas, planted about 3 years ago as a 6-7' tree. It is now about 12' but has not "flourished". It has put out virtually no horizontal branches, an...
view the full question and answer

Possible reasons for death of Wax Myrtle (Morella cerifera) in Austin
April 04, 2006 - Several wax myrtles in my neighborhood appear to have died. Should we have the soil or tree checked for fungus, or should we atrribute the death to freeze or age of the trees?
view the full question and answer

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