En EspaŅol

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
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

Saturday - October 20, 2012

From: Stockton, CA
Region: California
Topic: Non-Natives, Diseases and Disorders, Pests, Edible Plants, Trees
Title: Spots on non-native naval orange trees from Stockton CA
Answered by: Barbara Medford


I have two mature Navel Orange trees. One tree has developed spotty chlorophyl depleted areas that were not on the oranges when they were smaller. In addition, the oranges on both trees are smaller , by half, than normal for this time of year. Tanglo and Lemon on both sides show no sign of this problem..It really looks like something is eating small areas of chlorophyl.


Citrus x sinensis means it's not from around here, not even in California. Orange trees probably originated in Southeast Asia and were cultivated in China by 2500 BC. We always want to know where a plant is native, because that helps us know in what soils, rainfall and climate it grows well. The Lady Bird Johnson Wildflower Center, home of Mr. Smarty Plants, is dedicated to the growth, protection and propagation of plants native not only to North America but to areas where those plants grow naturally.

Even though we will have no information in our Native Plant Database on oranges, we will try to find some websites that might give you some clues:

University of Florida Extension Citrus Black Spot Symptoms in Brazil.

San Francisco Chronicle Citrus Fruit with Black Spots

To get information on a plant that is not necessarily native but does grow locally, we suggest you contact the University of California Cooperative Extension Office in San Joaquin County.



More Trees Questions

Is Robinia pseudoaccia a good replacement tree for Shumard oaks in Austin TX?
February 27, 2013 - Recently two of our Shumard trees in the front of our house died. Both trees were small/medium in size having only been growing for 13-17 years. I've been reading about Black Locust trees which accor...
view the full question and answer

Native plants for Pflugerville, TX in blackland soil
March 21, 2008 - Mr. S-P, I'm perusing the plant sale list for a couple of tall shrubs to plant on the sunny southwest side of my house, in Blackland soil. It is generally dry there because of the sun, but can ge...
view the full question and answer

Live oak bark splitting in Katy TX
October 03, 2011 - We have a 7 yr old live oak that looks like its bark is splitting open in branches and top leaves look wilted. If that sounds like oak wilt, do we need to have the tree removed? We live in a subdivisi...
view the full question and answer

Tree roots in sewer from Paragould AR
September 30, 2012 - I have beautiful pecan trees, an apple in the back yard, a pine on the west side of the house and pecan trees in the front yard. Two trees are interrupting my sewer systems (at least one in the back y...
view the full question and answer

Transplanting redbud from field in Edmond, OK
March 30, 2009 - I want to transplant a small redbud from a field to my yard. The trunk diam is about 1.5" and the tree is about 4' tall. What is the best way to do this? Should I plant it in a pot first?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2015 Lady Bird Johnson Wildflower Center