Monday, May 08, 2017

Pollinating Pawpaw flowers. 5.7.17

 I've been hand pollinating the pawpaw flowers for two days.  One of the challenges with pawpaws, is they don't self pollinate, bees are not attracted to the flowers, and most if not all require pollen from a genetically different variety.  The flowers first are receptive to pollen with a glistening stigma, then the stigma becomes non-receptive and the anthers bear pollen.  My observation is the flower is open and potentially receptive, one or two days before the pollen is shed.  The flowers do not open on the same day, instead blooming over a couple of weeks.  So if the temperature is not right, or if there is rain, all opportunity is not lost.

My trees for these varieties ("Sunflower" and "NC-1") were planted in 2012.  This is the third year they have bloomed, and this year is clearly the most prolific.  I also planted the variety "Rebecca's Gold" in 2012, it was then eaten off by a rabbit or deer, recovered, and this year is the first year that tree has bloomed.
In addition, I planted the variety "Mango" in 2015.  It bloomed in 2016 but not this year.  I planted the variety "Allegheny" in 2016.  It is not blooming.

Pawpaws do not transplant well, so they are planted when very small, and it takes more years to bear, compared to most fruit trees.

I should add that I have yet to see a ripe pawpaw in my orchard.  Will this year finally be the first?  I have noted that on the first, and sometimes second, year that many fruit tree varieties bloom, they do not set fruit.  Pawpaws are not native to the cooler maritime Pacific NW, and may have more challenges here than hot humid mid continent summers.  However, there are usually some ripe pawpaws at the Home Orchard Society fruit show, so I know that some people get them to grow and bear.

I use a paint brush to collect the anthers and pollen from flowers with ripe pollen, letting them fall into a white cup, then use a paint brush to transfer to flowers of the other tree.  Sunflower started blooming 2 days before NC-1, so this has been one-way so far.  However, Sunflower is also sometimes described as one of the rare self-receptive varieties, so I pollinated those with that tree's own pollen to see what happens.

2 comments:

  1. How do you remember all the names of your plants? Do you keep a record? You must! I have wild pawpaws in the woods, but I've never seen any fruit on them. Sometime in the past, however, they must have fruited.

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    1. Randy, I have them labeled. I cut pieces of beer can into strips with rounded edges, and use a paper punch to make a hole. I write on those with a ball point pen. That makes an embossed label. They are such thin metal that it's easy to cut with scissors, not like the old cans. I don't drink beer, but once in a while a generous motorist will throw one into my yard, probably knowing that I will put the can to good use. I do wash them before using.

      Pawpaws require a separate plant to pollinate. That's why they are not more common. Often in a patch, they are all genetically identical, growing from underground runners from the original parent plant.

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