since planting my mini plum tree 3 months ago it has grown at 100% its had one flower on but disappeared is this the norm can I expect more flowers as it is a well mature tree
I would not expect it to flower the first year. if it had set fruit it would weaken the plant. Unless it is a Victoria, it will need a pollinator.
if not a Victoria hows the best way to pollinate
You need another variety of plum that flowers at the same time.
Some other plums are also self-fertile, not just Victoria plums.
it won't produce any more blossom this year - spring is over.