My Pieris Japonica has healthy leaves but isnt flowering

it is possibly still not mature enough to flower.generaly if a plant looks healthy then it probably is

Pieris has red leaves only when they are new - as they age, they become green. So if you've had no red leaves (in spring, particularly) it isn't growing - is it possible it had a few red, young leaves back in the spring and you just didn't notice? The flowering is probably, as Noseypotter says, because it isn't mature enough yet.

Needs acid soil and some shade from morning sun. Mine did nothing much till I dug one up and put in a large tub with ericas compost. this year the flowers were spectacular and it was very red this spring. The other one still in the ground has done nothing so that is going to get the same treatment.

I had mine in a large pot for years and no flowers and little growth. Last year I planted it in front of a hawthorn hedge and it's doing well. My soil is more alkaline than acid. The hedge is very old and a few years ago I put a new gate post in. Unlike the rest of the garden the soil was perfect loam down to at least 3ft. whereas the rest of the garden is only a foot soil sitting on clay. I wonder if over the years the leaf drop from the hedge has enriched the soil. Anyway it made planting the post easy.

This doen't need to be mature to produce the red shoots, all new shoots should be red. Sounds like it's not growing which could be a problem of too much shade. Is it overshadowed by anything?

i thaught the question was to do with flowering

That's the lead in on this question, Nosey, but Jill also mentions the leaves "don't change colour"; no colour change, no new leaves, no new leaves, no growth, no growth, no flowers.

i guess so bamboo good point