Rent Shop Volunteer Join

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

Distressed Red Oak tree in Pflugerville, TX.
July 22, 2012 - I have a large (40 ft) Red Oak tree in my yard that is distressed. It started with yellowing leaves, with darker veins. Then small brown spots appeared, followed by browning arount the leaves edges. N...
view the full question and answer

Hypoxylon Canker removal in Austin TX
March 26, 2012 - I have several oaks that appear to have been killed by Hypoxylon atropunctatum from last summer's drought. Is it safe to cut them down in March or does that risk spreading Oak Wilt too. Should I ...
view the full question and answer

Aphid infestation from hackberries in Austin
August 22, 2010 - I've got 5 hackberry trees in my yard and they are all heavily infested with woolly aphids! I wouldn't usually mind, but the aphids are now all over my newly planted native plants. I've read up on...
view the full question and answer

Are Ashe Junipers dying from mite damage in Austin?
August 08, 2011 - If Ashe Juniper needles are turning brown and dropping off the trees because of drought, and not disease, do the needles ever come back, or have the tree limbs died? What if the cause is mites, not ...
view the full question and answer

New Jersey Tea shrub wilting and losing leaves
December 30, 2013 - I have New Jersey Tea shrubs transplanted last spring from nursery stock (18 tall, grown local) I live in SE WI. They are planted in part shade. There has been 6" of snow on the ground for weeks now...
view the full question and answer

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