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
2 ratings

Thursday - April 22, 2010

From: Waco, TX
Region: Southwest
Topic: Compost and Mulch, Soils, Trees
Title: Best fertilizer for live oak trees in Central Texas
Answered by: Barbara Medford


What is the best fertilizer for live oak trees in Central Texas?


Our vote would be "none." One of the big reasons for using plants native to North America and to the area in which they are being grown is that those natives are already acclimated by millions of years to the soils, climate, temperatures and rainfall in their area. We always recommend that the soil be checked, especially in terms of drainage, as most trees do not do well with wet feet, and too much moisture without sufficient drainage can cause rots and fungi to move in. We do like to see compost or other organic matter worked into the soil in the area where a tree is going to be planted, and not just the hole. As those trees get bigger and the roots move farther out, good soil with the amendments will help them to continue to grow. There are experts who recommend no amendments to the soil at all, because when the roots of the new tree begin to get out beyond their original hole, the real world, or the dirt thereof, could be a terrible shock. This is personal choice, but we like to give little trees a boost, partucularly in the alkaline clay soils of Central Texas.

Here is another take on that from a previous Mr. Smarty Plants answer:

"A standard fertilizer should be fine. One landscaper I interviewed advised an 8-2-4 compost-based fertilizer, meaning 8% nitrogen, 2% phosphorus, and 4% potassium. Others weren't so specific as to proportions, saying only "standard" or "regular."

All my informants said that if the tree is a naturally occurring specimen that has survived on its own without human intervention and still looks good, nothing may be needed. However, if the tree is now surrounded by new construction that may have damaged its roots, a fertilizer with significant phosphorus for root growth will help it adjust. Significant phosphorus will also be needed if your tree is a newly planted purchase that you want to encourage to spread its roots beyond its root ball.

All said that surface applications are best. Spread the fertilizer from near, but not on, the trunk, to a foot past the extent of the leaves.

A couple of friends of mine have maintained beautiful live oaks for two decades with little more than compost applied two or three inches thick from near the base of the tree to just past the dripline.

A deep, slow, soaking watering just after you fertilize will insure that the nutrients get to the roots. Doing it just before a good rain is even better.

Whatever you use should be applied once or twice a year. The most important time to fertilize is in early spring, just before new foliage appears, to help fuel the new growth. Though considered evergreen, live oaks (Quercus fusiformis, Quercus virginiana, or hybrids between the two) actually lose all their leaves in early to mid-spring, but the new growth appears about the same time that the old leaves drop, so most trees never look bare.

A second application in early summer can help fortify the tree during the harsh Central Texas heat."

So, take your pick; the point in both of these answers is that Nature is already doing a good job, you can give Her a little boost if you wish. 




More Compost and Mulch Questions

Source for pecan mulch used at Wildflower Center from Austin
November 11, 2011 - Hello Mr. Smarty Pants I was recently at the Wildflower Center. I saw all the pecan shell mulch and was wondering where you get it from. I noticed awhile back that it is one of the recommended mu...
view the full question and answer

Can non-native coleus grow in mulch from San Antonio
May 12, 2013 - Can Coleus plants grow in Mulch only?
view the full question and answer

Need Native Cover Crop in Seguin, TX
October 11, 2010 - Is there a native winter cover crop that would control erosion until spring vegetation takes over?
view the full question and answer

Erosion control on partially shaded slope
November 27, 2010 - Mr. Smarty Plants, I live in Atlanta, GA. My house is on a hill, and I am beginning to have erosion at my backyard porch (concrete slab, on the corners especially). The soil is mainly red clay, a...
view the full question and answer

Could ammonia harm poisonous, non-native oleander in Bay Point CA
December 20, 2009 - Could ammonia harm my Oleander plant? I have been spraying ammonia under it to keep neighborhood cats from using the soil under the plant as a sand box. If so, do you have any suggestions as to what...
view the full question and answer

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