|Olives with mossy growth inside|
|Olive mossy growth on the inside|
Olives are traditionally grown in Mediterranean climates; hot dry summers and cold wet winters. Olive trees are very drought tolerant but if they are being grown for their fruit then they must have adequate water during times of fruit production. Adequate water for trees is watering them deeply but infrequently. Deeply has to do with the quantity of water applied at the time of irrigation. Deeply means the water should be applied in a large enough quantity to water to a depth of about two feet deep in the soil surrounding the roots. If the water is not a good quality water, such as saline or water containing significant levels of salt, then it must be watered even more deeply to keep salts flushed from the roots.
|Olive flower racemes|
Now the mossy growth. This is where I am taking a bit of a shot in the dark. If these olives were planted 40 years ago they were olives that produced fruit. Fruitless olives were not being marketed then. There is no mention of fruit production. Olive flowers come out on clusters called racemes which also bear the fruit. If there is inadequate water (drought stress) the tree will have a rough time keeping these flowers and racemes alive and probably produce little to no fruit. My guess is that these are dried up flower clusters (racemes) that never were sustained for producing fruit either by a lack of pollination or enough water to keep the raceme alive and so the raceme dried up giving you the “mossy growth” you are referring to. But this is just an educated guess.