I have a twenty year old olive tree that yields thousands of olives and little olive trees sprout all over the place. I have transplanted several and they are now a few feet tall. Will they ever have olives or are they only good for shade?
Here is a story of reproduction without the birds and the bees. Technically, olive trees are hermaphrodites and bear both perfect flowers (containing both male and female parts) and imperfect flowers ( with only male parts).
Some olive varieties are capable of self-pollination while others must depend on cross-pollination with different varieties. Farmers will place "pollinator" trees in an orchard to ensure successful pollination and a good crop when the main variety is self-incompatible. Even self-compatible cultivars fruit better with a "foreign" pollinator.
Like other life which is propagated sexually, an olive tree will have traits common to both the male and female tress which were its progenitors. If it self-pollinates, then the olive seed produced will be similar to the tree it fell off of. Olive pollen can drift in the wind for miles, so if the olive is the result of cross-pollination from a different varietal, the seed will produce a tree with mixed traits. Simply put, the fruit from your seedlings which sprout all over may be different from each other even though they came off the same tree. They should all bear fruit.
Because of this uncertainty with seedlings, olives are propagated by cloning cuttings from the same tree. See propagating for the differences between trees created by different methods.
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