The Tropical Fruit Forum

Am I driving myself nuts for nothing chasing the US-942?

Yes!
A rootstock chosen for best commercial use for Florida is irrelevant to growing in pots in Montreal.
You have completely different climate, soil type and likely pests and diseases.
There is no published research on rootstocks for your conditions because there is no commercial imperative to carry it out.
You should consider the following points.
Tree size in pots is controlled mostly by the size of the pot.
If there is any danger of frost, choose a Poncirus trifoliata rootstock - but presumably in Montreal you keep heated in winter so that's likely irrelevant. However, it may be best against phytopthera root rot which can be a problem in cool conditions.
With possibly low light conditions in winter a vigorous rootstock might be best to get good growth for the months when possible. Most citranges and citrumelos are vigorous and root rot resistant. Here in UK, I find Rough Lemon good if you ensure excellent drainage. You will read that fruit quality is not the best, but at least it does produce results in imperfect citrus climates.

I don't think pollination of fingerlimes will make any significant difference to the amount of fruit produced.
As PAGNR suggests the main reason for lack of fruit is the tendency to produce male flowers without the capacity to form fruit. It is easy to distinguish any female flowers with the tiny immature fingerlime at the centre. I think these then can develop parthenocarpically without pollination, or be self-pollinated from the same tree, or be cross-pollinated from any nearby citrus. They can also drop off due to external conditions such as intermittent water, but probably not due to lack of pollination.
The percentage of female flowers seems to depend on maturity of the tree and on the particular variety or particular tree if a seedling.

I don't know what they are, but the nipple is not just a feature of lemons. Other citrus hybrids/varieties such as Minneola have them too. The dark orange colour is unusual.
Do you think this wooded area was originally a citrus grove? If so it would be a named variety or a rootstock left over from that period. If it is a 'wild' seedling from a dropped seed then it could be anything. A picture of the tree and leaf shape might be helpful. Also, the lower trunk to see if there is any graft visible.

These acidless oranges are apparently greatly appreciated in several North African countries, particularly by children.
I bought one from Italian grower Tintori a few years ago, specifically with the objective of trying to cross it with some of the hardy trifoliate hybrids. The idea was to eliminate some of the bitterness and acidity of the hybrids. However, when I tasted the fruits of  the Vaniglia orange I had bought, I found they were no different from other oranges. I still don't really know whether this is because the variety was incorrectly supplied or that my cool UK growing conditions do not favour the development of acidless fruit. So the hybridisation experiments never took place.

As a little Christmas present to myself, i ordered a presentation pack of some Australian stamps issued in 2019.
Yes, I know it's just a way of getting free money from idiots like myself - but they are very pretty stamps!




One of the stamps shows Lemon Aspen, Acronychia acidula, which is not a true citrus but it is in the same Rutaceae family.
I've been trying to obtain a plant or seeds of this species for a long time without success.
Can anyone help?
Mike/Citrange

I dont suppose you know of a source of Citrus. Garrawaye?

There were cyclone-damaged but still fruiting trees of C. garrawayi growing in Kershaw Gardens, Rockhampton when I was there in 2016.

There was a lot of reconstruction work there after the cyclone so I hope they are still OK. I contacted the local council to ask that they were protected but I don't know the current situation. See my webpage http://www.homecitrusgrowers.co.uk/australia2016/australia2016garrawayi.html
There are also publicly accessible plants at CSIRO Atherton and in Darwin Botanic Garden.

The cold tolerance error has been around for a long time. This is my explanation given on my website many years ago.
See http://www.homecitrusgrowers.co.uk/australiannativecitrus/eremocitrusglauca.html

This is a remarkable plant that grows in arid, near desert conditions, and can survive some frost. However, it is often said to be hardy to -24C.
This is definitely incorrect and arose from an error in the first edition of the reference book 'The Citrus Industry, Vol. 1.'
The book stated cold hardiness to......."ten or more degrees below zero Fahrenheit (-5.5C or lower)".    But zero Fahrenheit is far colder than -5,5C!
What was meant was.........................."ten or more degrees below freezing Fahrenheit (-5.5C or lower)".  This conversion would have been correct.
The second edition now corrected the wrong part of this error, making the conversion correct but the information wrong.
It claimed hardiness to........................"ten or more degrees below zero Fahrenheit (-24C or lower)."
 Evidence from USA confirms plants do not survive freezes of around -10C. It is probably hardy to about -5C in dry conditions.

There seem to be a number of different forms of C. ichangensis, or perhaps many of them are actually hybrids.
My plant, growing outside in the UK, produces a few fruits the size of a small lemon but with absolutely no internal flesh.
The skin is pebbly and inside is just a mass of stringy pith embedded with large seeds. Nothing to taste!
I will be collecting the seeds when ripe, so no photo of inside yet this year, but here is fruit and leaf taken today.

This looks very much like the damage caused by Citrus Hindu mite Schizotetranychus hindustanicus.
See page 11 at http://entnemdept.ufl.edu/Hodges/FL_FD/Documents/Plant_feeding_mite_pests.pdf
However, I can find no reference to this pest being established in Florida.
Perhaps you should report this to your local agricultural department or USDA, or discuss it with someone at  UF/IFAS Citrus Research and Education Center??

I think your autopsy may have missed something.
There seem to me to be several areas around the base of the trunk where the bark has cracked or rotted or been damaged.
Some possibly post-mortem, but a good wash in that area to remove remaining soil might help to see it.
I have tried to mark possibly damaged areas with a red line on your photo.
If there is similar damage all around the trunk that would explain the sudden death.

The limes have mature seeds. Are they worth germinating?

Yes - if you don't mind waiting a few years it's fun to see what you get!
Fingerlimes hybridize easily so you will most likely get some very variable seedlings and eventually fruits of different sizes, shapes and colour.

Put "citrus phytophthora" into a search website and look at the images. Many will show cracked, peeling and dead wood near the base of the tree - very similar to your photo.
Without laboratory testing and culture of the pathogen it is impossible to say what exactly is the cause. No doubt there are other possibilities, but phytophthora on citrus is very common and is therefore the most likely in this case.