How can I get more flowers on my Gardenia bushes?

Question

I have several gardenia bushes in my garden (they are in the correct soil - it is checked regularly for acidity level), they have lots of leaves, but not many flowers at all, some have none whatsoever. We live in South Australia in a temperate climate, and over the past 5 years that we have had these plants we have been happy with them, but have noticed that the number of flowers each year has varied on some of the bushes - one bush is always usually 'loaded' with flowers, except this year. Any suggestions on how to encourage flowers would be appreciated. The plants are fertilised and tendered regularly and given lots of TLC.

Answer 1

i would use superphosphate

Answer 2

I wouldn't add synthetic fertilizer.  It adds salt to the soil and is basically plant junk food.  Gives them a quick high but bad for their health.  Compost is the best.  You can make you own or buy a bag.  It is by far the best thing for your plants and they will in turn bloom to thank you.  

Answer 3

Blooming fertilizer. Any fertilizer with a high phosphorus % (the middle number).