Tenacity . The Aftermath. What your lawn will look like after using tenacity. In this video I am going to show what the results of using Tenacity look like. I had some grassy weeds in my lawn and treated them using Tenacity. Although I did NOT make a mistake using Tenacity I want to show what the results will look like in the lawn. Tenacity is a great product in my opinion for treating weeds. The problem with it though is the unsightly white spots that will show in the lawn. These spots are actually a good thing because you will know that the product is working.