Is Tree Of Heaven A Weed: Tips On Stink Tree Control

Tree Of Heaven Plant
tree of heaven
(Image credit: Gardening Know How, via Nikki Tilley)

No plant had more varied common names than tree of heaven (Ailanthus altissima). It is also called stink tree, stinking sumac and stinking chun because of its unpleasant odor. So what is tree of heaven? It is an imported tree that develops very rapidly and displaces more desirable native trees. You can control it by cutting, burning, and using herbicides. Grazing cattle on areas of growth may also help. Read on for more information on stink tree control, including how to kill tree of heaven plants.

Is Tree of Heaven a Weed?

You may wonder: “is tree of heaven a weed?” While definitions of “weed” vary, these trees have many weed-like qualities. They grow fast and spread quickly by suckers and seeds. They take over disturbed areas and shade out native trees. They grow where they are not wanted and are hard to get rid of. Although the lifespan of trees of heaven is not long, these trees dominate a site by their incredible ability to resprout. If you cut a tree, it immediately resprouts from the stump. The new spouts grow astonishingly fast, sometimes 15 feet (4.5 m.) per year. This makes controlling tree of heaven weeds very difficult. Mature tree of heaven trees also grow root suckers. These suckers often appear quite a distance from the parent tree. When a sucker finds a good growing spot, it develops into a new tree at a fast rate – shooting up 6 feet (1.8 m.) a year. Root suckers are, in fact, a tree of heaven’s primary defense. If you spray a tree with herbicide, for example, its response will be to send out armies of root suckers. Getting rid of the suckers in one fell swoop isn’t possible, since they emerge over the several years that follow a disturbance.

Controlling Tree of Heaven Weeds

If you are wondering how to kill the tree of heaven plants, the best method depends on the age and placement of the tree. If the tree is a seedling, you can pull it out by the roots. Be sure to get all the roots since a small root piece left in the soil will grow. You may think that cutting larger trees would be efficient, but the plant’s massive resprouting and root suckering habit make controlling tree of heaven weeds this way very difficult.

How to Kill Tree of Heaven

Given how difficult stink tree control is, you may wonder how to kill tree of heaven. If you can shade the areas before you cut, this will help you, since suckers and respouts die in shade. Cutting younger trees is more effective than mature trees since they have fewer established roots to send up sprouts. Repeated cutting – mowing once a month, for example – is advisable to eliminate the plant and its progeny. Burning the area for stink tree control has the same disadvantages as cutting. The tree continues to resprout and send out root suckers. Applying herbicides often kills the above-ground portion of the tree but is not generally effective in limiting or eliminating suckers and sprouts. Instead, try the “hack and squirt” method of applying herbicides to control tree of heaven weeds. The hack and squirt method requires a sharp hand ax. Use the ax to hack a series of cuts all around the trunk at about the same level. Apply about 1 milliliter of concentrated herbicide into each cut. From there, the herbicide is carried throughout the tree. This is a method of stink tree control that usually works. It kills the tree and minimizes suckers and sprouts.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.