A view looking up at Schefflera (octopus) trees that were treated with two different types of herbicide. The left side was treated with an herbicide nine months ago. There are still leaves on the branches. The right side was treated with another herbicide six months ago and all of the leaves have fallen off. Paul Zweng said the leaves were falling off after only two weeks of being treated. Zweng said he has been experimenting which herbicide works better on the different invasive tree species.