A number of my recently planted citrus are blooming, some for the third time this summer (including a number, such as the Page and Ponkan, which I didn't know to have multiple blooms). Our average date of first frost here along the Georgia/Florida border is mid-November, with the hard frosts typically coming in mid-to-late December. Does anyone know of a good source of information on the maturation period for various citrus and the cold tolerance of fruits specifically, so I can determine whether it makes sense to knock any resulting fruit off.

My inclination is to go ahead and knock the fruits off the sweet varieties, but I'm tempted to leave at least a few fruits on some of the cold-hardy acid varieties (calamondin, e.g.) to develop. Any advice, though, is welcome.
Thanks,
ES

I guess you think, that putting off helps the plant to grow better, right ?

I generally doubt that.
Trees invest in fruits only what not need to grow ...

That was my thinking. Even if the energy that would be devoted to the blooms and fruit isn't "needed" by the tree, it seems better not to have it wasted in the form of fruit that will never mature, right? With cooler weather setting in, most of the trees' energy will be put into root development, so won't that "excess" energy help develop a stronger and more extensive root system?

I say no !

It is that baroque idea, that the man rules the nature and therefore knows everything better ...
In real the nature rules and we are only a parasite in it ...

So it makes no difference if you let the fruits on or not, if the plant has not enough left over, then the fruits will just drop ...
Anyways it will invest only, what need not elsewhere.

If any of my single blooming trees where flowering right now I would remove them all. If there is a lot of fruit, in relation to the size of the tree, they will take alot of energy that would be used elseware. if there are a few, you could leave them on and see what happens. Obviously the production of fruit requires energy, so any energy not spent on fruit will be put towards root and stem/leaf growth. Most likely the fruit will be small and may not mature before the frost sets in anyway. One of the biggest reasons you should remove them is the tree will probably fruit stronger next year.

Some citrus will bloom throughout the year. My limequat & Calomondin are good examples, once they begin blooming in the spring they will continue to bloom until the first frost.

I think people are making way to big of a deal about this. Keep the fruit if you wish, dump the fruit if you don't.

First: From a fruit's beginning, through maturity, each citrus fruit only utilizes the energy supplied by the three closest leaves to it . All the rest of the leaves without accompanying fruit will supply all the energy the tree will need.

Second: Fruit produced from off season blooms are always lower quality fruit anyway.

If you want to keep a few, and hope there is enough time for them to mature, it won't make much difference to the tree one way or another. Your talking about the energy of only three leaves out of all the other leaves on the tree per each fruit you keep. If your tree is in reasonable health, it will certainly be no big deal to the tree whatever you decide.

Millet (164 BO-)

Now how did the scientists determine that the fruits are only supplied by the three closest leaves?

A bit of isotope ecology?
A bit of trial and error, picking the closest leaves off until the fruit was aborted?
Making it up and guessing that no one would call them on it?
Seriously, though, that's crazy.

The fact that only three leaves supplies the total energy to produce a fruit from bloom to maturity has been long known. If your interested in learning more about the botany of citrus, a good place to start your knowledge would be to obtain the books "The Biology of Citrus", and the four volume set "The Citrus Industry. - Millet