BarrierŪ is a selective herbicide for the control of annual and perennial weeds in established landscape and non-crop settings. Barrier is activated with rainfall or irrigation at temperatures above 60°F. After the active ingredient is washed off the granule, Barrier attaches to soil organic matter.
As the granules release the active ingredient, a "vapor barrier" is formed in the upper two inches of the soil. Barrier affects only the growing points of plant roots and shoots. Germinating seeds can't live within the vapor barrier and perennial weeds die when new growth invades this barrier. Barrier slowly kills existing shallow-rooted weeds and grasses. Deep-rooted, established trees, shrubs and certain groundcovers are not affected since their primary roots are well below the layer of vapor.
This unique method of weed control makes Barrier a perfect herbicide to use under mulch. Other uses include along roadsides and under asphalt.
Early spring applications are preferred. Barrier can evaporate quickly, therefore, immediate shallow incorporation or sprinkler irrigation is recommended. When the soil surface is hard or bare, the application should be incorporated as heavy rainfall can wash the granules from the area and possibly cause damage to desirable vegetation.