Potted citrus, keeping a certain size.

[Cristofre]

Obviously, trimming the branches and roots will keep a potted tree to an acceptable size, but what if the tree has not yet reached the maturity/size to flower/fruit?

For example, I have an unknown variety of citrus tree that I've had in a pot for like 7 years, but it got to be about 15 gallons and it was all I could do to get it inside for the Winter, and it still hasn't flowered or fruited.
If I trim it back so I can get it inside, am I just setting it back and guaranteeing that it will be forever a foliage plant, or will it eventually mature enough regardless?

[Millet]

Cristofre, trimming a citrus tree guarantees that the bloom will be either greatly retarded or even eliminated.  Citrus flowers on the newest growth.  When the tree is pruned the newest growth is removed and the tree's ability to flower is reduced or most likely eliminated. - Millet

[jcaldeira]

I severely pruned several citrus trees to relocate them.  The remaining foliage bloomed just fine, at the same age as my others.  I doubt you'd retard blooming by trimming where you need to.  However, as Millet indicated, less young growth means fewer flowers.

The most amazing thing I've come to appreciate about citrus blooming is that drought stress, and even physical damage, appears to promote flowering.  It's actually the re-hydration after drought stress that induces blooming.  It is almost as if the plant focuses on reproduction when its life is threatened.  I'm not recommending your threaten your citrus into blooming because its harmful to overall growth, but holding off with the water until some leaves start to curl does seem to induce blooming.   Some citrus growers control watering to achieve off-season fruiting.

[Millet]

Most citrus varieties are tip bearers, producing flowers and fruit on new growth which
is produced off of one year old growth. - Millet