If it does not have cocoons in this one month, this one is not going to bloom year.

Do not be how many years of life have.

If they are Camellias of flowering in early or average epoch, they will not bloom in this one winter.

Is it possible that they are very young Camellias obtained of seeds?

I do not believe that it is a problem of fertilization.

Some Camellia japonica (ex.=Anemoniflora alba) already are in full flowering together with the Camellia sasanqua or Yuletide.
Pardon for my evil English.
Regards.

{{gwi:514537}}

Here is a link that might be useful: Forum Camellias AEC

Generally , I've not had any problems getting blooms with just some supplemental feedings of an "iron" fertilizer, but is it possible they're in deep shade during the summer? They do like shade , but I'd think "dense" or low shade might be a bit too dark to encourage blooms possibly. Also , I bought a small cutting grown plant and it bloomed the next year, so it wasn't terribly old nor do they have to be usually to start blooming from cutting grown plants, but it's possible though not likely it's a 'seed grown" one.
And those could take much longer to bloom.