Q.Does junipers drip a oil onto grass that can kill the grass?
I have several juniper bushes quite large,was told if put new sod down must take out my junipers as they might kill grass if oils from bushes drip on grass
Juniper roots produce a chemical that impairs growth of susceptible plants (allelopathy). This is similar to, but not as problematic as black walnut. Also, junipers do not "drip oils". The bigger problem is the shade they cast and the density of their superficial roots. These roots outcompete grass for moisture and nutrients which effectively starves the grass. Because of the roots, it is very difficult to grow anything under juniper. I saw one study of juniper and 2 native western rangeland grasses that showed juniper allelopathy did not inhibit seed germination or growth. Juniper does affect native little bluestem grass. However, I found no information on lawn grasses which probably means the issue hasn't been studied. So we are back to the greatest known effect being dense juniper roots that virtually suck the life out of plants and dense growth habit that blocks sunshine from reaching plants underneath.
