In response to an old message about mulching I estimate that 60% or
more of the olives in our zone are permanent grass mowed in the spring.
Sometimes the hay is collected and sold - more often left as mulch. We have
found in our grove that skillfully timed mowing encourages the clover and
medic (annual species of medicago) which provide nitrogen for the trees.Our
rainfall is over 800mm annually so cultivation may be important in drier
zones but the price in terms of erosion can be high. I'm sure that many
people have seen the Spanish groves with trees perched on mounds as the
earth has eroded away because of erosion due to cultivation year after year
- decade after decade.

With young trees we kill the grass and clover by using a mulch of
newspaper. It is most effective and not as permanent as black plastic. To
stop the paper blowing away we cover it with fresh cut grass and
clover/medic. In our case it has worked well but the strong winds of NZ
might blow it all away? The mulch will last a couple of years provided it
is not churned up by the wild pigs.

Cheers Brian Chatterton.