Those allergic to olive pollen are well aware that olive bloom in Tulare County is usually expected in mid-May. This year, however, the bloom arrived by mid-late April during a cool period in the southern San Joaquin Valley.  The coordination of bloom with cooler temperatures is fortuitous for local table olive growers producing the ‘Manzanillo' olive for the black ripe industry. High temperatures at bloom limit fruit set of ‘Manzanillo' because the andromonoecious trees (aka: hermaphroditic) lack self-compatibility in the heat.  Under optimal weather conditions at bloom, ‘Manzanillo' is self-compatible, meaning that the pollen from a perfect flower may be transferred to the pistil of the same variety (or even the same flower) for fertilization. When warm temperatures occur at bloom (ie. temperatures exceeding 87^?F at bloom), ‘Manzanillo' pollen develops slowly resulting in reduced or no fertility. Growers mitigate the risk of heat at bloom by planting a compatible pollinator cultivar (ie. ‘Sevillano) within ‘Manzanillo' orchards, or by applying compatible pollen to solid blocks of ‘Manzanillo.'

On April 21, 2016, the olive block at Lindcove Research and Extension Center was approaching full bloom.