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
1 rating

Sunday - March 17, 2013

From: Round Rock,, TX
Region: Southwest
Topic: Compost and Mulch
Title: Use of free cedar mulch in Round Rock, TX
Answered by: Barbara Medford


Round Rock provides city residents free mulch to pick up. It is all cedar apparently. I am turning my now dead, mostly clay, very alkaline and rocky thin soil front lawn into a bigger flower bed of mostly Texas natives for butterflies and birds. I'm expanding a flower bed into the lawn to do so. I have a 20 year old bed of blue mist flowers the butterflies love and flame acanthus that hummingbirds love. I've added Damianita, Blackfoot Daisy, Rudbeckia, Frog Fruit, Skullcap (may not be native), Aster, Butterfly weed, and I also have already some antique roses into the lawn area and around the porch. Question: I want to use this free Cedar Mulch all around the new native plants on the lawn. I put a couple of layers of newspapers down, then a 4" thick layer of cedar mulch. Is that too thick? Is cedar mulch OK to use on a native Texas plant bed? I know you usually don't answer about roses, I have also mulched around a Mutabilis rose with the same cedar mulch. Perhaps a friend can answer that one. The mulch is already dried and on its way to decomposition, not still green, but it does have a few big sticks in it still. Any advice appreciated. Thank you so much for the service you provide!


Before we do anything else, let us congratulate you on your largely native-to-Texas garden you have been nurturing, apparently for many years. We are very tempted to say "whatever you have been doing, keep doing it." You obviously have also been choosing plants native to Central Texas, which can sometimes be a challenge with its alklaline, rocky soils.

To address your actual question, we are always in favor of using natural mulch, including that of shredded Juniperus ashei (Ashe juniper), better known around here as "cedar."  We are glad that cities are beginning to dispense this excellent mulch and discouraging burning cut-down Ashe junipers. You might be interested in this previous Mr. Smarty Plants article about using the wood ash from junipers to spread on the ground. Next, we suggest you read our How-To Article Under Cover with Mulch.

This article definitely emphasizes the many advantages of a shredded mulch, but also mentions some concerns, with which we agree. For some time, there was some discussion back and forth over the possibility of overdoing the mulch. One problem is that too much mulch around the roots of the plants can shelter insects that could be chewing on that plant, and may even promote mildew, which you don't want going on, especially on your (non-native) roses.

Another problem, chlorosis, might crop up if you have too much mulch around the roots. Please read yet another previous Mr. Smarty Plants answer (we are pretty lazy and don't like saying the same thing twice). That particular article is on Sophora secundiflora (Texas mountain laurel), but the same problem could apply. Also in that previous answer is a link to a university article on the process of chlorosis, itself. We hope you will read that too.

Summing up: We like what you're doing, and we know free mulch is very tempting, but you should watch out for some of the problems we have mentioned, and maybe back off a little on the depth of the mulch.


From the Image Gallery

Ashe juniper
Juniperus ashei

More Compost and Mulch Questions

Problems with Carolina Laurel Cherry from Pflugerville, TX
September 02, 2011 - In 2007 we planted 7 Carolina Laurelcherry (Prunus caroliniana)across our back fence. Everything was fine until this year. Three of the trees seemed to get sick and a local arborist said the roots ne...
view the full question and answer

Ailing Tecoma stans from Phoenix AZ
August 24, 2012 - I have several young Tecoma plants in my Phoenix, AZ garden. I planted them in June and have tended to them over the summer. They are watered twice daily. On some of the plants, I've noticed two oddi...
view the full question and answer

It's so hot, even the Salvia greggii are sad, in Bulverde Texas
July 28, 2011 - I have several Salvia greggii in large terra cotta pots. The leaves have developed a yellowish tint and are thinning. What is the best process to get them back to full green foilage?
view the full question and answer

Need evergreen hedge and groundcover for shade in Carmel, Indiana
September 27, 2010 - Our property is bounded by a fencerow that is wooded and mostly shaded by mulberry and hackberry trees during the growing months. We'd like to create a 5'+ tall evergreen barrier on the property li...
view the full question and answer

Planters for wildflower exhibit in Jemez Springs NM
November 28, 2010 - I am planning to have a wildflower/pollinator exhibit at a visitor center located on a high elevation grassland (no trees). I would like advice on the size of the planter boxes.The area is located at...
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