Some chemicals that can kill a tree are Triclopyr, 2,4-D, picloram, dicamba and imazapyr. Other chemicals that kill tree roots include glyphosate, triclopyr, picloram, 2,4-D and dichlorprop. Some chemicals to kill trees through the soil are bromacil, hexazinone and tebuthiuron. Dichlobenil and metam sodium are root killers for use in sewer systems.
Triclopyr, 2,4-D, picloram, dicamba, glyphosate and imazapyr are chemicals designed to kill smaller trees no taller than 15 foot high. The season when the homeowner attempts to kill the tree determines the best chemical to use. During the spring and early summer, it's best to use Triclopyr, 2,4-D, picloram and dicamba. In the heat of the summer, homeowners can use imazapyr, leaving the chemical glyphosate for early and late fall.
Triclopyr, picloram, 2,4-D and dichlorprop are used when killing medium and large sized trees with diameters of greater than 5 inches. Homeowners must introduce these chemicals directly into the tree by cutting the bark and injecting them.
For killing trees through the surface soil, homeowners use bromacil, hexazinone and tebuthiuron. After placing the chemicals on the soil, rain carries the herbicides to the roots and kills them on contact.
Dichlobenil and metam sodium kill tree roots that overtake sewer systems. These chemical form foam that gets into trees' roots.