While I am trying to study allelopathy in a petri dish, it is a very real phenomena that you can see. Come take a walk in the woods behind our building so I can show you:
This small sweetgum tree is hard to pick out from the push of other plants growing around it. Not so much right in front… I think they actually have mowed close to this tree… but behind, its wildlife city.
Here is another sweetgum (the large tree in the center), completely surrounded by rasberries, privet and uh, stuff. Not allelopathic.
Here is a panorama I took showing several walnut trees (to the right hand side) showing classic allelopathy. Unless someone has been mowing, *something* is keeping that forest to the left back. Black walnut trees raining chemical fire on its neighbor’s babies. At least we think…lots of other possibilities here (and actually there is a lot of data showing that the walnut’s roots are killing neighbor’s babies by secreting juglone from underneath). Get out of the house! The calls are coming from underneath the garden!!!!
To be honest though, if you pan all the way to the left, that mass of greenage has some black walnuts in it.. clearly not winning the allelopathy game.