I made a cutting 3 years ago from a double red flower Punica I selected the
branch when flowering and cut the following autumn
The cuttin is normally growing but no flowers

The double flowered pomegranate, in my experience, is not the best candidate
for bonsai. How big is the tree? Give it time & patience. Where do you live? It
needs to go outdoors for the summer. If the parent tree blooms for you, the new
one should bloom also eventually.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)