Answers to your gardening questions (by those in the know!)

I don't think it was lack of water, farmer. Perhaps the opposite?

We had the wettest summer on record this year:

http://www.theage.com.au/environment/weather/victorias-wettest-summer-obliterates-rainfall-record-20110218-1ayj9.html

After years of drought. And a very different summer ... humid, almost tropical conditions at times. Very different to the usual dry hot Melbourne summers.

I planted that tree during the drought, about 6 years ago, & it flourished much to my surprise.
Bumper crops, year after year.

Fruit drop is usully a result of stress of some kind.
Trees often respond to stress by flowering prolifically and setting masses of fruit. I guess hoping that some witll make it to maturity. when conditions improve the tree realises it doent need so much fruit and drops some until it reaches an equilibrium with available nutrient and water.
check the link below as it suggests some possible remedies

Fertiliser:
Citrus trees are very heavy feeders and require monthly applications of a good complete fetiliser complete with trace elements. Sure, before fertiliser was available citrus trees grew somwhere but only a few fruit ever made it to maturity.
Water:
Walk a distance away from your tree and dig down into an uncultivated area of ground about a spade depth or so. How dry is the soil? Its sometimes surprising how dry the soil can be at depth.

Temperature variation.
cold nights hot days at this time of year can sometimes upset fruit retention. The poor tree doesnt know wether its winter or summer.


Found this.
Premature shedding of citrus
This problem is a recurring one that is difficult to
prevent but the following explanation may help in
understanding the situation.
Normally about 98 per cent of the fruitlets
that originally set on orange trees shed before
reaching maturity. The remaining 1 to 2 per cent
is sufficient to produce a commercial crop of fruit.
Most of this drop or loss of fruitlets occurs at the
end of flowering or shortly afterwards when the
fruit is about pea sized.
A second fall, known as the ‘midsummer’ or
‘December’ drop usually determines what the
ultimate production of fruit will be. The fruit is
then 2 to 2.5 cm in diameter.
Trees growing in the sandy soils of metropolitan
Perth often suffer a very severe midsummer drop.
At this time of the year rapidly rising temperatures
and desiccating easterly winds intensify the fall
with the result that despite normally acceptable
care and apparent good health, the tree is
practically denuded of fruit.
http://www.agric.wa.gov.au/objtwr/imported_assets/content/hort/fn/pw/citrusloss.pdf

Not being an expert on citrus trees, I didn't know that Butrfkynet.
I'll do a bit of research to find out more.


Yes and I'd normally expect some droppage. But this year (because of the weird weather conditions) the number of flowers, then fruit, were quite prolific! And earlier than usual, I think. So I would naturally expect more droppage than usual ... but it seems odd that it's happening now & not earlier in the piece.
Maybe the tree is completely bamboozled by the strange weather this year?
There are still quite a few mandarins on the tree but I wonder how many there'll be by winter?
Apart from dropping so much fruit, the tree itself is flourishing!

Lawn or other grass will steal the water in the top few inches of soil Msolga. That depth is where a fruit tree has most of its feeder roots.
spray out grass at least to the drip line.
If you have neighboring trees sometimes a surprising distance away they will also be competing for water. maybe a drip line will be required.

Thanks for all that information, dp!
I'll take my time & read it carefully & see what I can find out.

Interestingly, my feijoa (sp?) lost all it's fruit this year. That's never happened before.
Both trees have grown like crazy, with really healthy looking leaves. It's the fruit that's suffered this summer.

in our orange grove work, the groves would spray Krovar at the dripline soil. This would cut down competition from weeds and preserve the drip water. Fla , even though the rain is plentiful, has really high permeability and rin can soak in within hoirs after a deluge.

I know nothing about orange trees but perhaps your problem is as simple as needing thinning (too many fruit to support good maturation of the fruit) a common problem.

There were way too many flowers, then fruit, Bob!
But I expected that problem to be sorted out well before now. (I was hit on the head yesterday by one of those fruit droppages. Ouch! The size of big marbles. )
And the tree (as well as every other tree in my back yard) has grown like crazy as a result of all the rain this spring & summer. Way too big & too bushy. I am now going to have to educate myself about pruning citrus trees, I can see that!

way too many flowers means may too many fruit. that's why the need for thinning.

Yes.

I'm having a low level spit fit. Some of us here have professional design expertise. Some others have owned ranches and farms.
Just about the last thing I want to do in my time off, and now long time off, is tell you what to do, when you don't seem to be trying to learn yourself, except to query.

Don't ask to be fed, do some searching. Then we can talk.

I think we already have talked about this on this thread, osso.

Don't worry yourself any further about it, please.

Obviously I am going to have to do more research, but as I said in my opening post (on this subject), I was more interested in others' opinions at this point. Generally a helpful starting point, for me anyway.

I don't really see a problem with that.

obviously?

Yes, obviously.

I've never successfully grown, nor pruned, a citrus tree before. And I haven't had a problem with this one till now.

Lucky you didn't plant a watermelon tree.

Or coconuts!

Missed that.

Better luck next year, MsO. Your tree must have been stressed by a weather extreme - wet or dry- and went into survival mode.

Yes, I'm afraid it's looking like next year, at this point, neko.
Oh well.
I think the unusual weather conditions might have quite a bit to do with the problem. I visited a (nearby) friend tonight & her mandarin tree is behaving in much the same way.

Moreover, only the rootstock - if it's a grafted tree- may survive ; you'd still have a tree sprouting up. Not a mandarin ,though.
Anyway, wait and see what happens. A bit of remedial pruning should suffice.