Plums and greengages are like pears; they all flower well before apples. This is why there is always a greater risk of damage to plums and greengages caused by spring frosts, when compared with apples.
However practice has shown that if a plum tree has not had a crop for one or two years, it usually manages to crop the following year. This occurs for two main reasons. Firstly, the tree seems to build up extra reserves to such an extent, that part of the blossom will set a crop whatever, if not all the blossoms do so. Secondly, not all the flowers open at the same time. This difference is important because blossoms that are still partly closed have a higher level of frost resistance, when compared to blossoms which are fully open.
However, with plums and greengages, often the reason for not cropping is completely different: PIGEONS. In the early spring, pigeons are often short of fresh green matter. Unfortunately at that time, pigeons can destroy a potentially good plum or greengage crop. Using cotton threads and scaring devices before the blossoms develop is the only way to deter them. Then there are the bullfinches, which love eating the flower buds any time from December to the end of April. If that is not enough to deal with, there is the pollination issue with plums. Some are self-fertile, but most are not. It is therefore important to make sure that the right varieties are planted together.
Click on the links below to read more about each variety.
Belle de Louvain
Coes Golden Drop
Mirabelle de Nancy
Old Green Gage
Ouillins Golden Gage
Rivers Early Prolific