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

Tuesday - April 09, 2013

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

QUESTION:

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?

ANSWER:

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 Soils Questions

Twenty year old Texas Mountain Laurel isn't blooming.
March 09, 2015 - I have 20-year-old Texas Mountain Laurel in a fairly poor, clay-type soil. It hasn't bloomed very well the last couple years. Can you recommend a fertilizer to improve the blooms?
view the full question and answer

Native landscaping and wildlife gardening in Clifton, TX
November 29, 2004 - I am moving to Clifton, TX, and I will have an empty lot in the town along with my own home/lot. What kind of soil can I expect? I want to grow a wildflower site to just sit and enjoy and feed the a...
view the full question and answer

Plants for red clay in Hattiesburg, MS
May 16, 2011 - Looking for plants and flowers to plant in red clay?
view the full question and answer

Yellow, pale green leaves on Cedar Elms in Texas
August 30, 2008 - I have had several cedar elms of various sizes planted in our yard over the last 10 years. Only the largest has dark green, healthy looking leaves. All the others have yellowish, pale green leaves. Th...
view the full question and answer

Native turf and trees for Odessa TX
July 29, 2013 - What native turf and trees can I grow in my Odessa, Tx back yard?
view the full question and answer

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