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

Tuesday - April 09, 2013

From: Austin, TX
Region: Southwest
Topic: Compost and Mulch, Soils
Title: Chlorosis on plants in Austin
Answered by: Barbara Medford


I have several plants that have chlorosis on the new growth. I did an at-home basic soil test. Ph came out at 7.5 (the highest the scale went, so it could be higher than that). Nitrogen and phosphorus are deficient. And there's a surplus of potash. The soil has a lot of clay. What do you recommend I do to amend the soil?


This is one of the reasons that the Lady Bird Johnson Wildflower Center talks so much about plants native not only to North America but to the areas in which those plants evolved. If your plants are not native to Central Texas, they are reacting to soils to which they are not accustomed.

From a previous Mr. Smarty Plants answer on chlorosis:

Yellowish leaves could indicate chlorosis, or lack of iron being taken up by the plant from the soil. This is often caused  by poor drainage and/or dense clay soil, which causes water to stand on the roots. Again, this could  be a problem caused by planting, perhaps without any organic material added to hole, or damage to the tiny rootlets that take up water and trace elements, including iron, from the soil.

Please read this article from the University of Illinois Extension on chlorosis. Note the comment that the presence of chlorosis is often due to high alkalinity in the soil. You can be pretty sure that your soil is alkaline, but plants native to this area are accustomed to that soil, and should be happy with it.

Among the steps we would recommend are to use some sort of iron supplement, not too much, as native plants do not ordinarily care for fertilizer. Water less, because it's possible the main problem is lack of drainage in soil where the plants are growing. Watering once a week should be adequate.  Finally, using a good quality organic mulch, spread the mulch over the root area without allowing it to touch the trunk area. This will protect the roots from heat and cold and, as the mulch decomposes, will add some material to the soil to assist in drainage.

From Texas A & M AgriLIFE Extension, please read this article on The Real Dirt on Austin Soils. If you would like to get a professional soil test packet, go to this site for forms and information.



More Compost and Mulch Questions

Pecan tree transplant in Elgin, TX
August 26, 2008 - Hello, Mr. Smarty Plants, I have a question about how to encourage a very young pecan sapling to grow, and whether I should use mulch to do so. I live in Elgin (Bastrop County) and the soil is extr...
view the full question and answer

Black-eyed Susans in potting soil on ground
November 12, 2010 - I would like to know if black eyed susans can be planted in just potting soil instead of mixing it in with dirt from the ground? I don't want to leave it in the pots. I want to plant it, but the grou...
view the full question and answer

Fruit in the compost bin
June 07, 2009 - I have a compost bin and I use the pulp from fruits and vegetables as one of the ingredients in my compost pile. We juice everyday so will all this pulp be too potent for new seedlings?
view the full question and answer

Should shredded Ashe juniper be composted for mulch?
May 06, 2009 - Our neighbor shredded some Texas Hill Country cedar trees. Can we use it safely as mulch? Do we need to wait until it composts some?
view the full question and answer

Gardening advice for Quebec
April 15, 2011 - I live in Aylmer Quebec 1. I bought some lily bulbs at a Christmas bazaar. When can I plant them and what do I put in the hole with the bulbs? 2. I bought a little potted cedar at COSTCO for a Ch...
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.
© 2015 Lady Bird Johnson Wildflower Center