Sprays used to kill cedar trees are called herbicides. Three types of herbicidal sprays widely used for killing cedar trees are Tordon 22K, Velpar and Surmount. Herbicides are powerful enough to kill cedar trees because they are composed of toxic chemicals and poisons, and must be handled and applied to the tree with extreme caution.
Tordon 22K is highly effective at killing cedar trees, with an extermination rate of 76 to 100 percent. This herbicide is applied in late winter to mid-spring, and before expected rainfall. Spraying trees with Tordon 22K is a simple procedure, requiring a handheld sprayer or syringe to apply the product all over the tree. Purchasing and spraying Tordon 22K requires a license, and the local county extension agency will have information regarding how to get certified to use this product.
Velpar can be sprayed on the cedar trees in the spring or fall. Rainfall or watering is required to activate the herbicide. Once the Velpar is activated, within three to six weeks, the tree should show signs of dying. However, it could take up to three growing seasons for the tree to be completely eradicated. Velpar is not a restricted-use product, so it does not require certification or permission for purchase or use. Purchase Velpar from a garden supply retailer.
Surmount is effective only on cedar trees shorter than 3 feet. The soil must have normal moisture before and after application of Surmount, and healthy foliage is necessary to absorb the chemicals. Use Surmount in late spring and early fall. This herbicide cannot be used during cold weather, or when temperatures fall below 50 degrees Fahrenheit. Surmount requires certification for purchase and application, so contact a local county extension agency to get a license to use this herbicide.