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Messages - citrange

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Cold Hardy Citrus / Re: U.S. 119...who is growing it?
« on: April 07, 2022, 04:38:56 PM »
I was given budwood of US119 in 2001, grafted it onto Poncirus rootstock, and planted it outside here in UK in 2004.
It has survived down to -15C, most winters the minimum is around -6c, but it has grown so slowly and never yet flowered.
I believe the real problem with growing citrus here is the short summer growing period.
We only have 3 months guaranteed frost-free and most varieties just don't have enough time to put on summer growth before they become dormant again.
My 119 is about 1.5m (4 - 5 ft) tall. Perhaps this year it will produce fruit - but I've been saying that for the past 15 years!

Cold Hardy Citrus / Re: F2 Citrus glauca
« on: February 27, 2022, 04:17:02 PM »
To be honest I can't remember whether they have seeds or not.
Although I had a look today, there aren't any fruits left - they all seem to fall together sometime in November.
I'll try and remember to check later in the year!

Citrus General Discussion / Re: Meyers Lemon Tree
« on: February 24, 2022, 02:42:21 PM »
If as you say this is a grafted tree then it seems the graft is very near ground level or below ground.
This means that it has been planted much too deep. The graft line should always be well clear of the ground so rain reaching the ground does not splash dirt on to the trunk and cause infection. That is one of the reasons for having a rootstock which is less susceptible to phytophthora than the top variety.
I think that the darker and slightly sunken area just below the main forking branches may be a sign of phytophthora infection.
If it is phytophthora and it has completely circled the trunk, there is little hope for the tree.
A really valuable tree could possibly be saved by grafting new rootstocks above the infection - a process called inarching.
This was carried out on the Parent Washington Navel tree in Riverside. See my photos at

Citrus General Discussion / Re: Meyers Lemon Tree
« on: February 21, 2022, 03:19:44 PM »
The whole tree is clearly dying, so the problem is almost certainly at the roots or trunk.
It would help if you post a picture of the trunk at ground level.
Is this a grafted tree or rooted cutting?
And what is the idea of that netting on the ground?
Here are three possible causes:
1.The roots could be rotting due to waterlogging and poor drainage.
2. It is simply too dry and not getting enough water. Once completely dry it can be difficult for water to penetrate and it runs off before reaching the roots.
3. There is restriction of sap flow in the trunk - usually caused by fungal phytophthera infection arising from physical damage or damp soil on the trunk.

Cold Hardy Citrus / Re: F2 Citrus glauca
« on: February 18, 2022, 04:24:44 AM »
Citrus glauca (previously called Eremocitrus glauca) does hybridise easily with other species.
Over 25 years ago I managed to germinate only one seed from several sent to me from Riverside.
It soon became clear this was a hybrid which I jokingly called 'Eremowhat?'.
This plant is still a vigourous potted tree about 8 feet tall and fruits each year.
You can read a rather old web-page about it at

Cold Hardy Citrus / Re: Dr. Robert Dunstan
« on: February 17, 2022, 05:50:29 PM »
I have just a small piece of information linking the names Zehnder and Dunstan which I was told about when researching the origins of a citrus tree in the English city of Nottingham. This quote is taken from my website at
However, I did have a lot of citrus seedlings raised from seeds a contact in the USA had sent to me and think this is where the connection comes from. I  received the seeds from a Mr Zehnder who said the parent plant was a citrumelo, not a citrange. He didn’t give me the cultivar name of the parent plant so I initially called the young plants ‘Zehnder Seedlings’ although subsequently he told me that the true name was ‘Dunstan’.

Citrus General Discussion / Re: Making mamalade
« on: February 14, 2022, 09:59:04 AM »
greatly reduces the heat destruction of the fruit
It may be a fun experiment but otherwise I don't understand why you are trying to do this.
Marmalade tastes good because the fruit has softened and broken down and partially dissolved in the sugar.
This probably wouldn't happen at your high-altitude boiling temperature.
Also, the marmalade sets to a gel or jelly because of the presence of fruit pectin.
I'm pretty certain that this won't happen at low temperatures.
There is a scholarly paper called SETTING TIME AND SETTING TEMPERATURE OF PECTIN JELLIES published in 1960, but you'll have to pay $12 to read it online.

Citrus General Discussion / Re: Grafting onto fast flowering Poncirus
« on: January 17, 2022, 04:57:00 AM »
Over the years I have read many reports on attempts to consistently induce early flowering in citrus seedlings. This has always been important commercially in order to develop new varieties. Methods attempted have included choice of rootstocks, height of grafting, hormone treatments, budding another flowering twig below the new graft, restricting sap flow by bending, etc. etc. As far as I know, none of these has been consistently and significantly successful. The exception may be the introduction of early-flowering genes from another species (arabidopsis?) but I'm not sure this has been used outside laboratory experiments and may not be acceptable to some people.
The idea that there is an early-flowering 'hormone' that can be transferred from flowering to non-flowering seedling has often been claimed - and named florigen - but never scientifically accepted or isolated.
I have grown early-flowering Poncirus seedlings for many years. Some seedlings do indeed flower when the plants are still only about 15cms/6" tall, but for me the flowers do not form fruits until the seedlings are bigger. And they are so slow growing that this takes many more years. I have not used them as rootstocks because in my cool climate I need something vigorous.
There are of course many anecdotal reports of inducing early flowering, such as the one by pagnr in this thread using FD rootstocks. He is lucky his FDs are flowering after 5 years - mine take 10 years or more! I also spoke to one French nurseryman who said that standard Poncirus seedlings flowered much earlier if a FD interstock was used.

Citrus General Discussion / Re: Grafting onto fast flowering Poncirus
« on: January 15, 2022, 11:41:15 AM »

Cold Hardy Citrus / Re: Yuzu seedling growing in Washington state
« on: January 15, 2022, 09:31:28 AM »
Interesting climate discussion - even if a little off-topic.
I'm sure much of what you say is correct but nonetheless Britain does very occassionally suffer what we call 'The Beast from the East'. This is when there is a prolonged period of easterly winds in winter originating in Siberia and blowing over northern Europe via Moscow and Berlin. It is usually associated with a strong Scandinavian high pressure system. Passage over water is limited to the English Channel which is only 20 miles across at its narrowest and then provides limited warming of a cold continental air mass.
You talk about Sweden. Remember that the Northern part of the Gulf of Bothnia usually freezes along with the Gulf of Finland and very rarely the whole of the Baltic. This is in part due to the very low salinity - in places the Baltic is nearly a fresh-water lake. In these conditions easterly winds reaching Sweden are isolated from any warming water. I doubt there are any outdoor Yuzus in Sweden!
Here is a photo of the English North Sea fishing port of Whitby Harbour frozen in 2010.

Cold Hardy Citrus / Re: Yuzu seedling growing in Washington state
« on: January 14, 2022, 07:41:10 AM »
I think I can beat you all with my Yuzu growing outside at 51.6 degrees N. That's a bit further north than Vancouver, Canada! We do however have the Gulf Stream to thank for our relatively warm winters. Usual minimum temperature around -6C to -10C.
My Yuzu is about six years old, planted outside three years ago, and currently carrying its first small fruit.
In the photos the thick branch behind is a Poncirus trifoliata and the orange fruits are a nearby Benton citrange.


Citrus General Discussion / Re: Low Biuret Urea
« on: January 07, 2022, 06:21:50 AM »
There is another very useful article about citrus foliar feeding, chemical deficiencies, toxicities etc at the link below. Contains a lot of interesting information - although of course it is directed at commercial growers and points them towards the company products. Includes picture of citrus leaves with biuret damage.
Here in England the amount of biuret in urea is rarely given in the product description, possibly because no commercial crops here are very sensitive to it. Sometimes it is said to be <1% but I have read that a truly low biuret product should be <0.2%.

Citrus General Discussion / Re: Remaking the Australian Red Lime Hybrid
« on: December 31, 2021, 03:35:50 PM »
Citrange are you growing a Blood Lime cutting or grafted on rootstock ??

Grafted - but I'm not absolutely certain on to what rootstock. Probably C. trifoliata (Poncirus) because that's what I have mostly had available but could also have been a citrange. I had a few Morton seedlings.

Citrus General Discussion / Re: Remaking the Australian Red Lime Hybrid
« on: December 31, 2021, 05:26:24 AM »
I have been growing a potted Blood Lime (or Red Centre Lime) for a number of years.
I find it is not a vigorous plant and has remained quite small in my less than perfect citrus climate. It produces a few fruits every year which usually remain a very dark purple-black colour until over mature. Finally they do reach the bright red colour usually seen in photos of this variety. I have several times planted seeds which germinate ok but produce very weak plants which die when still small.
For anyone interested in breeding from Australian citrus species, the CSIRO facility at Merbein did fantastic work. I have corresponded with Steven Sykes who led the research work there and he told me that all the experimental plantings and wild selections at the site were destroyed when it closed down. In my opinion that was an act of vandalism.
Here are a couple of GoogleEarth images of part of the site. They show the destruction between 2010 and 2012.

Citrus General Discussion / Re: Good citrus books?
« on: December 21, 2021, 04:55:48 PM »
Thanks for your comments about Home Citrus Growers website. I know it's style is dated and it takes quite an effort to keep checking that the links and facts are still correct. And it isn't designed for today's phones with small screens. Like me, it is getting much too old!
I'd love to have another plant-hunting trip in Australia but I doubt it will happen. The last one had its scary moments - I even ended up in a hospital having a live tick dug out from my chest. My wife thought I was quite mad to go poking around in the bush by myself. She's probably right.

Citrus General Discussion / Re: Good citrus books?
« on: December 18, 2021, 12:38:30 PM »
The Home Citrus Growers website has a list of citrus books
That's my website and a page I've forgotten about - so it hasn't been updated for 13 years!!
Nevertheless, many of these books are still a good read.
The Citrus Industry, Vol. 1 is still the most detailed botanical reference book covering citrus and related species, even though genetic studies have now altered the understanding of some relationships. It can be found through second hand book sites but is also available to read online.

Citrus General Discussion / Re: Variegated section on Pink Finger Lime?
« on: October 07, 2021, 02:01:42 PM »
The images in this forum thread are thumbnails linking to larger pictures - for example at
Can you not see either of them?

Citrus General Discussion / Re: Variegated section on Pink Finger Lime?
« on: September 30, 2021, 12:24:06 PM »
Theoretically every leaf is at a node point where a new shoot could grow.
So you could possibly take a small sliver of the stem bark, including that node with a variegated leaf, without seriously damaging the rest of the plant. Then insert that into a rootstock using a T-bud method.
Trouble is that everything is so small and difficult to do with a finger lime. And in practice, some leaf nodes are blind or take for ever to start growing.
I don't know whether additional light on a stem will make any difference to making a new shoot start to grow. Any opinions on this?

Citrus General Discussion / Re: Variegated section on Pink Finger Lime?
« on: September 30, 2021, 04:41:18 AM »
I've been growing finger limes for many years and always been on the lookout for variegated sports but never found managed to find any. So, you may be lucky but propagation could be difficult. Your photos show a few variegated leaves that appear to come from a small section of the main stem. If there is a separate shoot it would be much easier to propagate.

Citrus General Discussion / Re: Grafting on Severinia buxifolia?
« on: July 14, 2021, 05:43:43 AM »
I'm not surprised no-one has replied to this post because, unless you are a citrus research scientist, forum members don't have the capability of testing all the possible combinations of scions and rare rootstocks. Your 'big, satisfying tables' are the result of large-scale and long-term trials that most of us can't replicate.
I have a large collection of potted citrus and one potted Severinia buxifolia. It is about 6 feet tall and produces occassional small, black fruits. It isn't specially vigorous and I don't think it is frost hardy, so I've always kept it in a heated greenhouse in winter. I've never tried grafting to it. The only really odd graft I've attempted was a citrus on to a choisya. Why? - because choisya is a citrus relative and genuinely cold-hardy here in England. The bud stayed green for a year but never grew.
You mention incompatibility with Poncirus. I've never found any, at least in the short term. If you want a vigorous rootstock, I'd go for Rough Lemon or a citrumelo. Commercially, they may not be ideal for quality fruit production, but for the hobby grower I find they give quick results.

I'm amazed you can't get horticultural grit. It is available in every garden centre and plant nursery here.
I think you need to take a day trip to England and collect a few good garden items!
The chipped bark sold for reptile bedding or orchids is extremely hard and dry. I agree it must eventually break down, but in this mix it lasts for at least 10 years.
I did try and use coconut husk chips at one time. They only provided good drainage for a couple of years before causing problems. I suspect coir will be similar.

Living in southern England I have very similar climate to yours in Belgium.
I have been growing citrus for very many years and I now always use the following mix which is very free draining but requires frequent watering in hot weather. It contains no nutrients so I add slow-release fertiliser granules initially and every spring. I also water always with dilute soluble fertilser. I have included some links to suppliers in the UK so you can see what I use but you can probably find equivalents locally.
Following parts by volume:
2 parts clay granules. This is a type of moler clay about 2mm diameter. It is sold for bonsai but is much cheaper to buy in quantity as Sanicat cat litter or as a chemical spill absorber. See and
1 part coarse pine bark sold as reptile bark or orchid bark. See
1 part horticultural potting grit  see
1 part coarse perlite This makes the mixture a bit lighter but can be omitted. See

Citrus General Discussion / Re: mealybug destroyer ladybugs
« on: July 04, 2021, 05:06:26 PM »
The trouble with mealybugs is that the seem to be able to hide and reproduce in the tiniest cracks and crevices in the tree bark. So even if you wash them all off the leaves they quickly re-appear from somewhere else. I've even found them in quantities under the rim of my pots, and recently discovered that they are infesting the centre hollow of the bamboo canes I have been using.

Citrus General Discussion / Re: Satsuma tree help, leaf drop
« on: May 11, 2021, 05:39:54 PM »
Yes, the mottled leaves look like typical spider mite damage.
Miticides, horticultural spraying oil, or frequent washing are all control methods, but the mites are tiny and probably too small to see any remaining on your photos.
Unfortunately the affected leaves will not recover and some may fall off.
Eventually the tree will produce new shoots which will grow normally if the spider mites have been eliminated.

Cold Hardy Citrus / Re: US-1284, SCS rootstocks
« on: April 16, 2021, 02:52:21 PM »
As you are in zone 7A I presume these will be kept as potted plants.
There is very little relevance in the published information which applies to potted plants.
All the research is directed to commercial growers of in-ground trees.
Tree size will depend to a great extent on pot size.
Cold-hardiness of rootstock doesn't matter if in winter-heated conditions.
HLB and some other insect-borne diseases won't occur.
Soil pH is controlled by whatever planting medium used.
The one thing I find important - unless you are really careful with watering and drainage - is rootstock susceptibility to phytophthora root rot.

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