Wednesday, May 11, 2016

Mid-way through pecan pollination season

  The last few days of warm sunshine has really promoted the progress of pecan pollination season. Cultivars with the protandrous flowering habit (pollen early, pistillate flowers late) have released or are currently releasing pollen form fully ripe catkins. The photo at right shows Gardner catkins with many open pollen sacs that have started to turn brown in color since all the pollen has already been released.
Looking over at the terminals of the Gardner tree's new growth I found numerous clusters of pistillate flowers (photo at left).  Gardner, like all protandrous cultivars, produce pistillate flowers late in the pollination season. The stigmas of Gardner flowers turn red and glossy when receptive to pollen. The flowers pictured at left are just about ready to capture pollen from the air.

   In contrast, the pistillate flowers of protogynous cultivars have already been pollinated. The photo at right shows a cluster of Posey pistillate flowers.  The stigmas of Posey flowers are green in color but note the the upper edges of the stigmas are starting to turn brown and look dry. This is the first sign that these pistillate flowers have received pollen and are on their way to setting a nut crop.

  The pollen sacs on Posey catkins are only now starting to turn from green to yellow (photo at left). It won't be long before these pollen sacs will begin to open and release the pollen needed to fertilize the pistillate flowers of protandrous cultivars like Gardner.