What Do You Know About Allelopathy?
Reprinted from California Chapter Newsletter
What do you know about allelopathy? No, it isn't like homeopathy. This is the inhibition of growth of plants by toxic chemicals produced by another. Possibly this explains your lack of success growing plants beneath Eucalyptus globulis or redwoods. Both have water soluble inhibitors on their leaves which are transferred to the ground by drip from the leaves. Not all plants are affected by these chemicals, but it is surely worth remembering when these trees are near your garden. The tannins present in the leaves of oaks, pines, walnuts and madrones prevent some plants from growing beneath them.