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Friday - September 12, 2014

From: Arlington, TX
Region: Southwest
Topic: Problem Plants, Trees
Title: Live Oak Suckers or ??? in Arlington, TX
Answered by: Larry Larson

QUESTION:

Do I have live oak suckers or an invasive plant? We bought a house a few years ago in Arlington, TX with two beautiful old live oak trees, and mostly just bare sand-dirt under them. Under one tree was what we thought was Asiatic jasmine. I started planting a garden, watering and fertilizing, and the growth under the trees started to spread. We hit the area with the weed eater, and put town weed cloth. The bugger's shredded the weed cloth within a year. The next summer i tried roundup, and I bought gallons of the stuff over the course of the summer. I finally gave that up and decided it was too many chemicals to be good for people, and it wasn't working anyway. Last fall I covered one area with thick black plastic, and I have spent this summer mostly ignoring the problem and trying to think of ways to contain it. The roots go very deep, and just barely under the dirt is like a woven net of roots. Even the black plastic didn't stop them, peek underneath and it looks like a net of tangled white roots, just waiting. The other sections do not seem to be acting like Asiatic jasmine, they are getting a foot or two tall, and not running along the ground at all. It�s like a dense thicket. I read the answers on live oak sucker treatment, but how to I know if that is what I have? If it is, I can live with it, but not if it is spreading Asiatic jasmine. How do I know? The leaves are not smooth like live oak leaves, they look almost like holly leaves, and are waxy and thick.

ANSWER:

From your description, Mr Smarty Plants’ vote goes for Live Oak Suckers. The Quercus fusiformis (Escarpment live oak) trees in my front yard actively grow suckers, so I’m out there pretty frequently beating them down. They are actually part of the tree so it’s pretty hard to keep them down without harming the tree. [I shudder at the thought of “gallons of Roundup”]

Here’s what struck me in your description that makes me think these are Oak suckers. You described a mat of roots, thick under where the suckers grow. That is how they grow, and the suckers emerge from that root layer as shoots [growing straight up forming a “motte”]. They will easily, within a year, reach a foot or more high and pretty much grow straight up. Here’s a video presentation from the Central Texas Gardener on ball moss and oak suckers, they show a picture of the motte of suckers that is pretty typical. [Have patience, it’s in the last minute of the video]. You also described: “The leaves are not smooth like live oak leaves, they look almost like holly leaves, and are waxy and thick.” This does sound a lot like Live Oak sucker leaves. Here’s a picture of those sucker leaves from “Daves Garden” and here’s another one from the gardenweb forum.

In contrast, here are similar pictures of Asiatic Jasmine leaves from Daves Garden. They seem to me to be a bit more rounded in the center, and lacking the points that I interpreted as what you were describing as “like holly”. Also, do the plants spread beyond the limits of the tree? Suckers will only emerge from the roots, Jasmine will escape and aggressively move beyond the tree.

I hope that clarifies in your mind whether these are Oak suckers or Asiatic Jasmine. If it doesn’t, then perhaps you need the direct on-site assistance you can get from a skilled arborist or perhaps a Master Gardener. Here is a link to the Tarrent County Master Gardeners.

While I’m at it though, while only partially successful, here are links to some comments on my efforts to control the Live Oak suckers.

Live Oak Suckers
Live Oak Suckers Reprise, Austin TX

From the Image Gallery

Escarpment live oak
Quercus fusiformis