Contact Us Host an Event Volunteer Join

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

Sunday - August 08, 2010

From: Austin, TX
Region: Southwest
Topic: Planting, Transplants, Shrubs
Title: Sumacs under live oaks dying in Austin
Answered by: Barbara Medford

QUESTION:

Converted my yard to native plants last fall. All of the fragrant and evergreen sumacs are dying off one by one - they have never thrived. I ensure they get a good soaking at least once a week. I was warned not to fertilize them or it will make them deer fodder. They are placed as understory for our live oaks and mulched with a couple inches of oak leaf/hardwood mulch. What can I do to save the few that are left?

ANSWER:

Can we assume that the sumacs were planted when you did your conversion to native plants? If so, they have not been in the ground very long, and could still be suffering from transplant shock. We always check growing conditions on the page in our database for plants that are not doing well, and ask ourselves "Is this a plant in the wrong place, or the wrong plant for the place or was it planted at the wrong time?"  According to this USDA Plant Profile for Rhus aromatica (fragrant sumac) it is not native to Travis County, but does grow in some counties to the north and east. However, according to this USDA Plant Profile, Rhus virens (evergreen sumac) is native to Travis County and several counties in the vicinity. Both require sun (6 or more hours of sun a day) or part shade (2 to 6 hours of sun), and tend to develop into thickets in open fields in the wild. Since they both are native to this area, we can assume they are in the right place in terms of soil, climate and rainfall. 

So, what's left? You say they were planted as understory trees to live oaks. There is a lot being said now about the allelopathy of oaks; that is, emitting substances that discourage competition from other plants. These substances can be present in fallen leaves, roots, and bark. If the oak trees were already well-established, it just may be that there is not room in your space for both, and the oak trees are winning.  Perhaps even the amount of water they are getting is inappropriate, as the growing conditions for both include low water use, dry soil, and tolerance of drouth.

If you have seen no insects or signs of disease on the sumacs, and they are supposed to be very resistant to both, we can only assume that the environment is wrong, including being planted beneath oak trees and mulched with oak leaves.  How to help the remaining ones survive? You could try limbing up the live oaks to create more sunlight, cutting down on the watering, and raking away the oak leaf mulch. Will those work? Sorry, we simply don't know. 

We want to caution you about limbing up or pruning your live oaks. From the Texas Oak Wilt Information Partnership comes these precautions about pruning live oaks, which are being devastated in Central Texas by Oak Wilt.

"All wounding of oaks (including pruning) should be avoided from February through June. The least hazardous periods for pruning are during the coldest days in midwinter and extended hot periods in mid- to late summer. Regardless of season, all pruning cuts or other wounds to oak trees, including freshly-cut stumps and damaged surface roots, should be treated immediately with a wound or latex paint to prevent exposure to contaminated insect vectors."

From our Native Plant Image Gallery:


Rhus aromatica

Rhus aromatica

Rhus virens

Rhus virens

 

 

 

More Planting Questions

Trees safe near walls from Rio Grande City
March 24, 2012 - What trees can be planted near the house that the roots won't break my walls?
view the full question and answer

Native grass mix for Bastrop County, TX
February 25, 2014 - I plan to put in a small lawn on a tract of land near Rosanky, TX in Bastrop County. There are scattered oaks but the yard space will be mostly open. Soil is basically sandy. Is there a good native...
view the full question and answer

Removal of previously-planted perennials
July 23, 2008 - HI I JUST MOVED INTO A NEW HOUSE THIS YEAR THE PREVIOUS OWNERS PLANTED A LOT OF BEAUTIFUL PERENNIALS BUT I WANTED TO PLANT OVER ONE OF THE PERENNIALS THAT I REALLY DO NOT CARE FOR. IS THAT POSSIBLE? I...
view the full question and answer

Young pecan trees with leaf and branch problems from Gatesville TX
November 18, 2013 - I have a young pecan tree that had very rapidly browning Leaves. They became brittle and so did the branches with affected leaves. The branches soon fell off. We treated with fungicide during that pro...
view the full question and answer

Putting in native grass in June in Manor TX
May 31, 2012 - We are moving into a new-built house in the middle of June. We opted to not have them put in Bermuda grass as we wanted to seed a native mix. From my understanding, mid June will be too late to start ...
view the full question and answer

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