In case anyone was completely bewildered or curious, all of these rare Japanese varieties mentioned are closely related to both Yuzu and Satsuma mandarin.

For a more specific pedigree on exactly how, you can see the diagram in this thread: origins of Asian hardy citrus types - diagrams

These particular varieties are hardy, but only zone 8 hardy, I don't think they would do well in zone 7. They are not as hardy as Poncirus trifoliata hybrids. I think it should be considered a miracle that any type of edible citrus can be grown in the Pacific Northwest climate.

Those are Beautiful citrus plants you have there. Im looking to add a few more citrus plants to my garden so and ill definitely look up the ones you have. Currently I have i have 2 Lemons, 2 Pineapples, 1 Guava, and 1 Orange growing outside, in ground in Tacoma, WA.

Are the lemons surviving for you outside over the winter?

How long have they been in the ground? Do you put any type of covering over them?

What type of lemon are they?

Yes they survive the winter. They are placed on the south side and east side of the house. I put incandescent Xmas lights on them through the winter and the warmth from the lights seem to be enough. The fruit is usually ready late winter early spring. The big lemon tree has been in ground 4 years the smaller lemon and orange have been in for 2 years. They are Meyers Citrus

Wow, so you just put lights on them but they are not actually covered?

I think Tacoma (at least the parts of the city closer to the water) gets milder temperatures than Olympia, despite being a little further north.

They are only half covered by the over hang on the roof but that's so high up it provides very little cover, but yea the Xmas lights keep the bulk of the plants nice and warm. The only thing that takes damage are some of the ends of the plants. They get frost bitten but when it warms up you just cut it off with your normal pruning.

Justin the correct spelling of the word is Christmas

Here is an update August 10, 2021

This is the Ichangquat x citrumelo hybrid seedling, getting a little bigger and putting on some growth. It is about 18 inches tall.

Here is a update picture of the Bloomsweet. It is growing and starting to reach some size and establish itself.

Here is the very tiny Keraji seedling that has survived in the ground for a few years without protection. It lost its leaves earlier in the year (perhaps due to slugs eating the leaves) but it has now regrown some new leaves. The leaves are small and not too big but look decently healthy. This thing is very small, about an inch, less than two inches high. I'm not sure if it will ever eventually be able to put in some size. It seems to suffer a setback after each winter, but then very late into the season, around late July, it starts to recover but then there is not much growing season time left in the year. It looks about the same now as it did the same time of year last year, and the year before that. But it is amazing such a tiny seedling is surviving and not declining.

Here is the bigger Keraji, more medium sized like something newly planted, that's grafted on rootstock. It is doing well. It had tiny little fruit druplets begin to form but it looks like most of them dropped off.

X-mas lights are what I use too.

Just make sure to get the old school incandescent Xmas lights, the new led ones don't give off much heat.

Here's the latest update
October 3, 2021

sorry for the low resolution images, was trying to fit 4 images into one picture to help reduce data space

A - tiny keraji seedling
B - Ichang papeda
C - Sudachi
D - ichangquat seedling (regular seedling)

The coloration on the tiny keraji seedling looks green and a very healthy color. However, this seedling just overall does not seem to be putting on any growth. It was the exact same size this time last year. The winters seem to set it back and then it recovers, but it does not seem to be able to grow to a size bigger than it was before. Those little leaves are all new. (There are five leaves, two of them very tiny)

Most of the leaves on the Ichang papeda are still very light in coloration, yellowish-green. I would say more yellow than green though they are still obviously alive. It seems they were never able to green up much since the winter. If you look carefully, there are a small number of newer smaller leaves that are a little bit more green in color but even those leaves do not look a healthy green. There are two of these Ichang papeda plants right next to each other and the leaf coloration on both looks exactly the same. Perhaps this variety begins to put out its new leaf flush too early in the year, when it is still too cold, and so the newer leaves do not develop the most healthy greenish color. When the very small new leaves initially start growing, they are a dark reddish color. I have never observed this growing them inside. It probably is a natural response to growing outside, either to the ultraviolet light of the sun or the cold.

The color of the leaves on the Sudachi look just okay. Not really the healthiest deepest shade of green, but okay, still definitely green and not yellowish. This little plant has not been able to put on much growth. It is a slow grower.

I may be mistaken about this but the Ichangquat seedling has not been able to grow any new leaves. All of those little leaves you see on the seedling are all old, from 3 years ago, the leaves that did not fall off (most of them did). But amazingly those leaves look like a healthy deep green color. It seems obvious those leaves have been able to recover. I think this seedling has almost not been able to put on any new branch growth. Yet the recovery of the leaves and the fact they have fully recovered their color since turning very yellowish during the winter is a good sign.

(This is the normal Ichangquat seedling, not the other one that seems to be hardier that I suspect is a hybrid)

I would say that all four of these are managing to survive, but almost not putting on much growth. Very slow growing. It seems they are marginal growing in this 8a Pacific Northwest climate. None of them were protected or covered this winter.

Bear in mind these are not big plants.
I took some measurements. The tiny keraji seedling is only 2 inches, the Ichang papeda is 14 inches high, the Sudachi is just a little over 16 inches high, and the ichangquat is 13 inches high but very narrow, with only 3 leaves.

Here's the latest update from Christmas morning, December 24, 2021

Bloomsweet grapefruit

Keraji mandarin

I'd say the leaves on the Bloomsweet and Keraji are both green, with just a little bit of yellow splotches in the Keraji and some light yellow-green color on some areas of the Bloomsweet. Still not an unhealthy color, considering the temperatures and time of year.

Changsha mandarin (that's an Escallonia bush in the background)

Although you can see some snow and ice, temperatures had not really gotten that cold at the time of these pictures. Ambient air temperatures had not actually gone below the freezing point yet. The leaf coloration still looks pretty good in all three pictures. I'd say the leaves on the Changsha look the best, but it is somewhat protected by being half engulfed by that big bush.

However, temperatures tonight (December 26) are expected to go down to 18 °F, and the temperatures are not expected to rise above freezing for the next 4 days, which is an unusual thing for this climate. (It more often stays just right above the freezing point) Apparently there is Arctic air coming from the interior of Canada. It's actually colder here right now than in Minneapolis or Buffalo (although of course that will not last too long).
I put some paper grocery bags over both the Bloomsweet and Keraji with containers of water under there as well. They are not too far from the house. Right now there's about 6 inches of snow on the ground.

Your best shot to save the citrus would be to cover them completely with mulch or compost until the freeze is over. That will form a blanket and utilize the heat from the ground. Paper will not keep much heat in, and can actually cause more freeze damage than it prevents. But it is better than plastic. Good luck. I was in the same position last Feb in SE Texas.

Can you get some Christmas lights on them? The incandescent old school kind. Also cardboard boxes to place around it at night? Your jn WA state correct?

Just to emphasize again, these are all special varieties of citrus that have much more cold tolerance than normal varieties of citrus. Which is why I don't have to go to as serious lengths to try to protect them (which is the whole point). I'm eventually hoping that they will reach a size where the plant could be able to survive on its own even if it was not covered. Of course, I think the plants will recover faster and put on more growth the following year if they are covered, which is important because it's hard for citrus to be able to put on much growth throughout the year in this climate (the temperatures being too low for a large percentage of the year).

I only covered this Bloomsweet and Keraji because they are not quite as cold tolerant as the other varieties I am growing. You might say they are the most vulnerable of my cold tolerant varieties. I might put on a covering just during the very coldest part of the winter. The cover might only be on a few days out of the entire year. The temperature most winter nights here these varieties can handle.

"Special varieties" means they are edible, but are not really good eating quality like the varieties you would find in a supermarket.

The Bloomsweet can supposedly handle down to around 16 to 18 F, the Keraji down to around 12 to 14 F, Changsha somewhere down to around maybe 10 to 12.5 F. Though the leaves can suffer some moderate to light damage on the lower end of that.

I think you'll be fine then. Your plants look the same as mine when they were small dealing with winter. Eventually they will hold there own. This is one of my lemons a day before it snowed here in wa. I let it grow a little wild so that any frost damage that happens can be cut back in warmer temperatures and minimal damage is done to the plant.

Do you cover your lemon during the winter? If not, which city are you in?

I do see that lemon seems to be planted close to the wall of your house.

What variety of lemon is that?

Here are two pictures to give you some idea what the snow is like here.

Yuzu on grafted rootstock

Not citrus, but a (somewhat) rare Rhododendron yuefengensis

related thread on that here for anyone who's interested: Rhododendron yuefengense

pictures taken December 31, 2021

Some additional (low resolution) pictures, so you can see how some of these look in the winter.
Pictures taken January 15, 2022

Here is what the leaves on the Sudachi look like

Ichang papeda

These both had plenty of snow cover. The ones that did not get the benefit of snow cover have leaves that look fried now.

very small Yuzu seedling (on own roots)

Putting a first aid radiant barrier sheet over your tree will offer the same protection as snow covered leaves. You may have to put a bed sheet over the plant to keep the plastic from touching the leaves.

This is so interesting! Where did you get your plants? I live on a hill and we get about 5f colder than the valley and it seems like often 10f lower than Olympia or Tacoma, usually when I forget to cover something.

Curious why you try to grow plants that are marginal in your zone? And it's a real curiosity, not implying you shouldn't.

I want to grow citrus. It's mostly just the idea of being able to grow citrus - and I mean big trees out in the yard. Not smaller plants in containers that I have to fuss over. I want citrus trees as a feature of the landscape. And according to research I had done, I realized I was in a marginal climate zone where that might not be entirely impossible, if I got some very rare unusual varieties. Right now it's sort of like a collection where I try to get as many rare different varieties as might be able to grow outside here, while still trying to pick the ones that won't have a flavor too terrible.

Growing subtropical things helps make me feel that the temperatures are warmer than they actually are - like I'm striving/fighting against nature. (I'm not much of a fan of native area plant gardens, as you might have surmised)

ann beck, my location is not too far away from the water of the sound, so temperatures here probably do not go down as low as they do in the more rural areas like where you are.

More power to you socal...Is the SoCal part of your name implying you want to be gardening in Southern Callif.?

I like a wide variety of plants whether they're natives or not. I have two main rules learned over many years of gardening (read that as making mistakes). They can't be invasive and they can't require special care. I provide good soil, water and keep them from fighting with each other too much. In return I get a lovely place to enjoy a glass of wine.