Safest Way to Kill Oleander Roots That Are Wrapped Around Water Pipes
The oleander (Nerium oleander) is grown along highways and as a hedge in U.S. Department of Agriculture plant hardiness zones 8 through 10. The white, pink or purple flowers on the evergreen shrubs make them an attractive option in commercial and home landscapes, despite their poisonous nature. The oleander's twisted roots tend to invade water pipes, making it necessary to kill the plant and its roots before they break the pipes and cause expensive plumbing repairs.
Protect Yourself First
While your concern may lie with your pipes, oleanders contain a highly irritating and poisonous sap that may wreak havoc with your skin, eyes and lungs. Shoes or boots, long sleeves, long pants, gloves, safety goggles and a dust mask are recommended safety equipment when working around oleanders. If you are a smoker, avoid the habit while pruning or applying herbicides; the dead foliage and some herbicide formulations are extremely flammable.
Prune It Down
Prune the oleander to within 6 to 8 inches of the ground. Begin pruning around the outer perimeter of the shrub, removing the small, outer branches first and working your way inward to the larger stems and trunk. Cut the branches into small, manageable sections and place them in garbage bags. Don't put oleander in the compost pile or burn it; the sap remains toxic even after the death of the shrub.
Generally a brush-killing herbicide is applied to the oleander's stumps. If you use a ready-to-use glyphosate and triclopyr herbicide, spray or brush it generously over the exposed wood within 15 minutes of cutting the stem. The cambium, or green inner layer between the bark and inner wood, pulls the herbicide into the shrub and down to the roots, killing them within four weeks. If you select a 2,4-D and triclopyr herbicide, follow the manufacturers directions carefully when mixing 1 cup of herbicide concentrate with 6.25 gallons of kerosene, diesel or fuel oil. Spray the stumps thoroughly with the herbicide solution to ensure that the cambium layer is completely covered.
Once You've Killed the Oleander
Oleanders have large twisting roots, but once you've killed the shrub, the plant won't regrow from the roots. If no sign of regrowth appears within four to six weeks, your efforts at killing the oleander were successful. If water pipe repairs are needed, you can dig up the area and remove the roots. Otherwise, simply dig down far enough to cut the remaining stumps below ground with loppers or a saw. The dead roots will eventually decompose.
Clean Up The Mess
After you've finished pruning the oleanders and applied the herbicide, clean all your cutting tools with a solution of equal parts water and rubbing alcohol. Allow the tools to dry before putting them away, out of reach of children and pets. Rake up all the oleander leaves, twigs and debris and place them in garbage bags for trash pick up. Wash your clothing in hot water and detergent to remove any oleander sap.
With degrees in fine and commercial art and Spanish, Ruth de Jauregui is an old-school graphic artist, book designer and published author. De Jauregui authored 50 Fabulous Tomatoes for Your Garden, available as an ebook. She enthusiastically pursues creative and community interests, including gardening, home improvement and social issues.