By Jon Trappe
Many plant enthusiasts have observed difficulty planting some plant species around black walnut trees. Black walnut trees naturally excrete chemicals into their environment to make themselves more competitive. This negative plant-on-plant interaction is known as allelopathy, and is more common in multiple plant species than was once previously thought.
There have been a few reports (Bertin et al., 2009; Bertin et al., 2003) of natural weed suppression in certain fine fescues (Festuca spp.).