Alistair Macdonald wrote:
Last year and the year before my mature (about 20 years old) Victoria plum
tree produced barely half-a-dozen fruits. This year I have harvested over
300 delicious plums. What, if anything have I done right, or do the
elements take the credit?




It can depend on a wide variety of things,
not necessarily in this order:

proper pruning
insect pollination
weather, wind
temperatures
fertilizer/nutrients
just plain luck


Some fruit trees produce a big crop every-other year
alternating with a mediocre one.

gloria p