No fruit this year on greengage plum trees

Since moving to this Victoria property 8 years ago I have had good crops every year on my greengage plums. We make jam and chutney every year. I have 6 trees and this variety is found around the neighbourhood. Seems it will sprout from seed. This year I have only two plums on our entire property. What happened? No pollinators? My small apple trees and pear tree are doing poorly too. The image is from 2014.

 

I found only one apple on our tree in Sechelt this year. It bloomed quite heavily, but it was cold and very rainy when it did. Many plants in the Botanic Garden here are having a very floriferous/fruitful year. Some magnolias had their blooms killed by the cold, but others bloomed very nicely.

 

Thanks for your thoughts Eric. We had lots of blooms too. I suspect lack of pollinators.