When and how should I trim a pomegranate shrub that is now 12ft tall?

Question

I planted a pomegranate shrub which was about 3 feet tall at the time of planting about 5 years ago.  This was a transplant from a prior home.  There was a logical division noticed when transplanting, so I divided into two plants.  One plant has grown to about 5 feet tall and has never had a flower bloom or fruit, even though the plant appears to be healthy.  The second division has grown to 12 feet tall and it too is healthy.  Last year there were a couple flower blooms and I was able to pick one rather small but tasty fruit.  This year there were zero blooms.  

I have purchased two more plants which are about 6 feet tall each, rather leggy, but each is many flowers.  I plan on planting them today in approximately the same location, but about 20 feet apart.  All plants receive sun.  

My question is how I should prune the plants that have been planted for several years so that they will have blooms next year.  I will wait on doing any pruning on the newly planted shrubs for a year or so until they have time to acclimate to the area....unless someone advises me to do differently.

Thanks.

Answer 1

You did not mention where you live but they do well in Texas.  Trim late winter into early spring & stop.  It depends on which variety that you have for fruit.  If you want to keep them as bushes trim off suckers or else it will grow into a tree.  feb, may & sept devide 2 cups of ammonia sulfate and keep grass a ft or 2 away....mulch to hold soil moist.........Happy summer.  We can't grow them up in 5a so enjoy them.