Citrus > Cold Hardy Citrus

update on hardy citrus collection in PNW, April 2021

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Ichang papeda

another Ichang papeda

This one came from a rooted cutting.

The leaves on both Ichang papeda plants have turned a very pale yellowish color.
They did this after the last winter too, but were later able to start putting out some new leaf growth at the start of June.

Dunstan citrumelo

Looks moderately okay. Leaves are still green but a little bit of a yellowish hue. The leaves will probably start to green up more later into the year.
I notice the trunk has gotten thicker than it was last year, so it is getting bigger.


This one is on rootstock.

Changsha mandarin

Leaves look a yellowish hue of green. This one is in a very protected location, so I'm surprised the leaves don't look more of a healthy color.

Keraji mandarin


Both the Keraji and Bloomsweet were covered with a paper grocery bag, with a one gallon water container up against them inside, just during the several coldest days of winter in mid February. They are also planted in an optimal location, not too far from the house, on the south-facing side.
You will notice the leaves on both look a surprising dark green color, a good sign because normally the leaves turn yellowish from the cold.

All pictures taken April 1, 2021
Olympia, WA, climate zone 8a

The plants are not too big, most of them I would say are around a foot and half tall, some more or less.

This might help give some of you a better idea of how these different varieties do in the Pacific Northwest climate.


This one is growing in the back up against a fence, far away from the house.

tiny little Keraji seedling in the ground, on its own roots

It is still alive, and has now gone through three winters so far, but has not grown too much. It's only a little over 2 inches high.
I am hoping maybe if it is able to put on a little more growth, it might be able to start growing faster. I do realize that trying to grow Keraji here on its own roots is probably very marginal. It was an experiment.

Ichang lemon, in a container on the deck

The leaves look a pale green color. This was left outside all winter.

This I believe is a "MIC", in a container

supposed to be a ((Temple orange/tangor x trifoliata) x Ichang papeda) x Minneola tangelo hybrid , although there is not much information about it
So far it does not seem to be proving very cold hardy. I had another one of these planted against the fence far away from the house and it was killed after an unusually cold winter 2 years ago.
The leaves look like a pale kind of yellowish shade of green. Those leaves are probably not going to be able to recover, although it will grow out new leaves.

I am hoping this might have potential for further breeding.

Ichangquat seedling, on its own roots

grew this from a seedling. This has been its second winter in the ground, unprotected.
I'm not sure it got the best luck of the draw when it came to cold hardy genetics. Most of seeds appeared to be zygotic. When it was originally first planted it looked very healthy and vigorous. Last year it wasn't able to grow a single new leaf. All those leaves that you see on the plant have been there for two years. I think the leaves may still technically be alive, but probably not very functional. The leaves look a very pale yellowish color. The thin little trunks of the plant still look green though, a moderately healthy color. It might manage to put out a little leaf growth later.

There's also another Ichangquat seedling (not pictured here) with leaves that look a great dark green color right now. I suspect that one might have been pollinated by citrumelo, however, so its hardiness might not be representative of Ichangquat.
Indeed, due to Ichangquat seeds being very zygotic, it could be the case that the seedlings would be expected to show a range of different cold tolerances.
(not a subject I want to get too much into here)

very interesting Socal, thank you. Could you still tell us what have been the lowest temps and how long have been the time of consecutive frost days to get a better imagination of what the plants had to take - thanks Frank

This has been a cold winter, a relatively long winter too (although that's typical for this region), although this has been a relatively mild winter in terms of how far the temperature has dropped. I think it only went down to around 22 F (-5 or -6 C).

What it has felt like, this entire "winter" season has really been more like a cold spring (springtime season), with the exception of a week in the middle of February beginning the 11th or 12th. I mean one could find a few camellia and rhododendron bushes with some fresh flower blooms on them throughout the winter, except during that single time interval when there was snow. But that is not atypical for this area.

There were a few light frosts before then and after then, of course, but those temperatures were barely just below freezing. Certain types of plant species were able to continue putting out some flower blooms despite those frosts.
But it was still a cold winter in the sense that we did not have any warm spells, and the temperatures were pretty much constantly and consistently cold.

Two years ago it did get down to 12 F (between -11 and -10 C), again in the early half of February. The Dunstan citrumelo and Yuzu shown in the pictures were in the ground then and survived that. The Bloomsweet was in the ground too then but had a covering over it, although with a vented fabric top, although since it was covered with a deep layer of snow that probably insulated it when the coldest temperatures came. It suffered some fairly severe bark damage at the base of the trunk but was later able to recover, even though I wasn't sure it would. The Yuzu suffered some moderate bark damage at the base of its trunk too. That was the same time when the tiny Keraji seedling was killed down to a half inch above the ground, although as you can see in the most recent picture it was able to partially recover.

Thank you SoCal, very interesting, so we had much more temperature differences and a week with 5 days frost night and day and temperatures down to 3 degree Fahrenheit ( - 16 degree Celsius) and every day 100% full sun which made it worse.
But as far as I see I only lost my Dunstan, all other Citrus survived with more or less damage and some as Morton and  HRS899 a or Ivia and Prague start to get new buds.
If I can reliably report for sure damages and recoveries in some weeks I will make a short report with comparisons and pictures.
best regards Frank


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