Camellia japonica is very good for hedges.
I know big hedges of Camellia japonica in Galicia (Spain).
But this annual growth, which you want for your Camellias, I believe that she is not possible.
To obtain one I peeped or more of annual growth only can be obtained in very good conditions of culture.
And a lot of varieties grow towards the sides and little in vertically. In the collection of more than three hundred elderly and modern Camellias of Soutomaior's Castle, it is possible to observe the growth of many of you them will cultivate. 
Good varieties of vertical growth: MORNING GLOW, PRESTON ROSE, ORANDA-KO AND SAWADA. The densest hedges and more recortables for having the small leaves, are obtained by species of Camellia as: Camellia sasanqua, Camellia vernalis or Camellia wabisuke 
Camellia japonica cv.'SAWADA'
The Camellias grow very much, but they need many years to develop her height. In order that they grow well you have to obtain:
To cultivate adapted.
Appropriate climate.
Appropriate soil
Good fertilization.
Good taken care of gardening.
Good luck.
The best thing that you can do is to buy Camellias of the definitive size. To give form to the Camellia and to support them in the height that you want. 
Camellia's plants, which stand out as hedge, lose many flowering. The flowers are born in the apexes of the branches.
Due to this circumstance, it gets used to planting hedges, the Camellias of simple flower, obtained of seeds.
Pardon for my evil English.
Regards. | 
