Whether you want to kill a mature palm tree (family Arecaceae) or those tiny sprouts that pop up year after year, an herbicide can do the job. However, it's important to weigh the pros and cons of using an herbicide that kills palm trees. They affect the environment, can cause injury to people if used improperly and may kill nearby plants. The safest way to use herbicides to kill a palm tree is to paint them onto a cut stump rather than spraying the leaves.
Herbicides That Kill Palm Trees
The most effective herbicides for palm trees include triclopyr or its derivatives (such as triethylamine salt or butoxyethyl ester), picloram and 2,4-D. These chemicals kill palm trees the same way: They mimic a growth hormone called auxin to an overwhelming degree. The plant cannot cope with the resulting surge of uncontrolled growth, and it dies.
Both of these herbicides have the potential to cause harm to the environment, especially near water. For example, the ester forms of triclopyr and 2,4-D have been linked to the death of fish and aquatic invertebrates, whereas long-term exposure to picloram can cause liver damage in mammals. It's critical to follow application instructions to the letter to avoid contaminating waterways, killing nontargeted plants and affecting the health of other living things.
Triclopyr is sold under brand names like Garlon 3A, Garlon 4, Turflon Amine, Turflon Ester, Brush-B-Gone, Crossbow, Redeem, Remedy and more. Picloram is sold as Grazon PC, Tordon K and Tordon 22K. You can find 2,4-D in products like Barrage, Lawn-Keep, Plantgard and Savage. Many products contain a mix of herbicides; for example, triclopyr and picloram are included in a brand called Access.
Preemergent Herbicides for Sprout Prevention
It's common to see dozens of palm tree sprouts under a mature palm tree. Spraying these with an herbicide that will kill palm trees is one option, but sprays must be handled with care and applied on days with little to no wind. If you'd rather not go through the hassle of using a spray but don't want to spend hours digging up the sprouts by hand, try a preemergent herbicide, like trifluralin or oryzalin.
These herbicides are scattered on the ground under the palm tree before it drops its seeds. The seeds will not be able to germinate, and the ground will stay sprout-free.
Killing Palm Trees With Herbicide
Always read the product label before applying any herbicide. These products can cause serious eye damage or lung irritation, so always wear eye protection and a respirator. Never spray an herbicide on a windy day.
To kill a mature, tall palm tree, the tree should be cut down by a professional arborist to prevent the dead trunk from falling and potentially causing injuries. Then, an herbicide can be painted directly onto the freshly cut stump to prevent regrowth. Painting versus spraying the herbicide also cuts down on accidental damage to nearby plants caused by drifting particles.
Palm sprouts can be killed by spraying the leaves with the herbicide, but several applications may be necessary.