Stopping Volunteer Trees – Managing Unwanted Tree Seedlings

Weed Tree Seedling
weed tree
(Image credit: vili45)

What is a weed tree? If you buy the idea that a weed is simply a plant growing where it isn’t wanted, you can guess what a weed tree is. Weed trees are volunteer trees the gardener doesn’t want – unwelcome houseguests who arrive without invitations. What should you do when you find young trees you didn’t plant springing up in your backyard? Read on to find out your options including tips on how to get rid of volunteer trees.

What is a Weed Tree?

Weed trees are not a special kind of tree. They are unwanted tree seedlings that grow in your yard, young trees that you didn’t plant and don’t want. The status of “weed tree” is determined by the gardener. If you are thrilled to find the seedlings, they are not weed trees at all but volunteer trees. If you are not thrilled and want to get rid of volunteer trees, they qualify as weed trees.

About Unwanted Tree Seedlings

While a weed tree is not a species of tree, many unwanted tree seedlings fall into a handful of species. These are types of trees with high seed germination rates, fast growing trees that colonize quickly and choke out the slower-growing species. They are usually not native trees in the area. Trees that tend to fit this description include:

  • Norway maple - throw off many winged seeds
  • Black locust - self-seed easily and are invasive
  • Tree of heaven - a Chinese native that multiplies by root suckers (not heavenly at all)
  • White mulberry - also from China, with edible berries that birds spread around the neighborhood

Some other “weed trees” may get planted by squirrels, such as with oak trees. Squirrels will often stow away acorns from the tree in various parts of the landscape for later. And occasionally fallen acorns that are missed by birds or squirrels will germinate.

How to Get Rid of Unwanted Trees

Once you determine that a volunteer tree is a weed tree, act quickly to pluck it out of the ground. The earlier you try to remove the seedling and its roots, the easier it will be, especially if you water down the area first. The key is to remove all of the root system of the unwanted seedlings so that the plant will not regenerate. If that moment has passed and the unwanted seedling is already well-rooted, you’ll need to try other techniques. You can cut down the tree and paint the stump with full strength weed killer or regular paint to kill it. Keep in mind, though, that the toxicity from the use of chemicals may spread to other areas of your garden, killing other plants or making the ground infertile. Some suggest girdling the weed tree, since this effectively cuts off the canopy from water and nutrition from the roots. But this may take a long time and is probably not your best option. To girdle a weed tree, cut a one inch (2.5 cm.) or more strip of bark off from around the trunk. Make sure to cut deep enough to penetrate the hard center of the trunk. Doing this will slowly kill the tree over a period of a year or two and reduces the chances of the tree producing suckers.

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.