I've been told hardy citrus needs to be larger (maybe 2 to 2 1/2 feet tall) and grafted onto trifoliate rootstock for it to have a chance of surviving here. I knew very small seedlings would be more vulnerable to cold, but just wanted to see how they would do.

I also had a theory that citrus growing on their own roots might be hardier in this climate and be able to regrow faster. That doesn't really seem to be true, if this test was any indication.

I do have some other hardy hybrid seedlings that would probably survive outside here, but these varieties that were tested here are "medium" hardy (level of hardiness is all relative of course).

There's a general inherent trade-off between hardiness and edibility, with the hardier varieties tending to have worse flavor and lower levels of edibility.

And in fact I do have a Yuzu, just a little over 1 foot tall, grafted onto trifoliate rootstock that managed to survive outside unprotected and still has most of its leaves. (in a warmer spot near the south facing side of the house)

Well, it does look like the Yuzu seedling is technically still alive, although it doesn't look well at all. No leaves, but I still see some green on the stem, and there's a little green bud where the last leaf fell off.

It now has several leaves on it.

Apparently the heat wave has really helped it grow out.

Giving it some water right now.

Good luck little yuzu

The Yuzu seedling looks like it is recovering, several medium small leaves growing out of it.

Go Yuzu go!

It'll be quite the battle getting that to any size. Have you thought about giving it any protection over winter?

The growing season here (temperatures that are warm enough for citrus to put on growth) is from very late May or early June to about the middle of September.

Because it's so far north, the length of daylight is also longer, which can help plants put on more growth during the short growing season. That's one of the reasons vegetables here can grow to enormous sizes.

In case anyone was wondering, here's a close up view of the Keraji seedling. It's tiny.

The Keraji seedling still appears to be alive. You can see budding of tiny little leaflets beginning to grow out of the stub in the ground.

This was the same tiny seedling I posted a picture of before that had one tiny leaf. Unfortunately there was an accident several months ago when the gardeners came through and lopped the top of the seedling off, so it lost that tiny leaf.

Hey, I thought your winters were as bad as mine up there? I can get to below 0 with a lot of snow.

From what I see, you are far warmer than I am and I wish I could do that. Great job.

Unless yo have more time to pull and baby a keeper....then put it back out

have more,

looks like the tiny keraji seedling is recovering

only about an inch tall but I think I see the beginnings of some strong leaf growth now

Yuzu seedling

July 1

It now seems to be rapidly growing.

Awesome job, Thanks for sharing !!

It's a big investment in time, but grafts high up on P. trifoliata rootstock tend to be hardier. It is theorized that the large amount of trifoliate trunk (say 2 to 3 feet at least) exposed to the cold imparts a deeper and longer dormancy to the scion.

Keraji

It's still very small, and recovering, but vissibly growing

four very small leaves now

keraji seedling with bigger leaves now

keraji

yuzu seedling

July 24

It's almost back to the same size it was in August last year.

Looks really nice.

Steve

Go, little yuzu!

yuzu

Aug 13

Aug 25

The seedling is bigger than it was this time last year.

Here's the little keraji seedling

Aug 27

maybe only a little more than an inch tall but has several little leaves which look a healthy green color

The little keraji seedling is beginning to put on some more growth

Meanwhile the Yuzu seedling has reached 10 inches tall and looks very healthy.

Yuzu seedling, almost 11 inches tall now

Sept 5

Do you intend on protecting it?

Perhaps it will make history, worthy of a place in the annals of MT museum of agriculture along with its owner.

The Yuzu seedling was not protected last winter. But it was planted in a very optimal location, I do have to say. I had wanted to put some light protection over it when cold temperatures were forecasted in February but there was a freak snow storm and there was no way to get to it. It was probably buried under at least a foot of snow though, and I think the gardening people there laid down an inch and a half of mulch (fallen leaves) over the soil in that spot before the snow fell.

It's most likely the next winter will be less cold than the last winter.

If it's a mild winter it will be interesting to see if it can make it through without stem die-back.

It would certainly be a sight to see if there was a big fruiting Yuzu tree growing outside in this part of the country. So far I have proved it's possible for a seedling to survive, but it's still premature to say whether it can do well and grow to be a much bigger size. (I mean it might be that it will just be killed back every winter and have to start all over again like it did this year)

I think the fact that such a small seedling was able to survive a harsh winter bodes very well, because a larger plant with thicker diameter stems should be able to tolerate cold much better.

Especially the fact that it was not grafted onto poncirus rootstock. Being on its own roots, that's going to allow it to grow much faster and more vigorously, I think, though it may not have as much cold hardiness as it would on poncirus.

I'm keeping it consistently watered, because the summers here tend to be pretty dry. With the size it currently is, I don't think it would be able to survive if it wasn't watered.

My trials also seem to confirm that Yuzu has a greater level of cold hardiness than Keraji, which is what one would have expected. I was hoping the Keraji would have done better, but it was a colder winter than usual with a lot more snow than is usual for this area. They looked like they were doing fairly well and that the leaves would have been able to make it, until the beginning of February.

Yuzu seedling, 12 inches tall now

Keraji seedling

The rainy season has started now and the temperatures are cooling off. Yesterday stayed around 60° F for most of the day.

Sept 18, 2019

Thanks for keeping the updates coming! Hope they make it through this winter. You inspired me to try it - I'm leaving a red lime seedling out this winter. (I'm in NC/8a).

The little trees look good, thanks for regular updates! What are your plans in terms of cold protection for them?

Just found this, I'm very invested in this little yuzu

Here's the yuzu seedling, Dec 15, 2019

I'd estimate it's about 14 inches tall now.

It looks great, thanks for the update!

This is super cool and I love it

I hope you help the little guy along with some protection. merry xMAS

Here's the Yuzu seedling today, January 26, 2020, still looking good

I also planted a little Ichangquat seedling next to it.

The Ichangquat should be even hardier than Yuzu.

This is a rare one you can't buy. This just went into the ground, so I expect the leaves will turn white and fall off before it grows new leaves in the late Spring.

Again, this is in Olympia, Washington State, climate zone 8a.

You don't commonly see citrus growing outside in this area, so these should be unusual curiosities for this area.

And it has been a pretty mild winter so far.

tiny Keraji seedling

February 13, 2020

It's looking good.
it wasn't protected.

I noticed a camellia bush in partial bloom in a neighborhood on the way through Tacoma, also saw a pink rhododendron bush in full bloom near a big apartment building in a semi-protected spot. I even saw a few flowers of something that looked like jasmine, although most of the bush had brown dead leaves. So far it's been a cold but "green" winter (meaning the temperatures haven't really dropped too low).

Here's the little Yuzu seedling, February 25

It seems to be doing just fine.

It's doing much better after this winter than it was the winter last year. I know I posted a picture of it a month ago, but I thought it worthwhile to update it today because February 25 pretty much marks the end of winter and we are not going to have any freezing temperatures after today. If it could make it to now, it will do just fine the rest of the year.

If any of you really want to go see it to believe it, you can go to the Yashiro downtown Japanese garden. A little seedling that doesn't have poncirus in it is surviving outside in Olympia, this far north in latitude (47 N). Not merely just a plant but a very small seedling, on its own roots, not grafted. Of course I feel it is in a protected spot in a very optimal location, and being situated downtown probably also helps temperatures from going to low. But it does demonstrate the climate Yuzu can grow in. A very interesting experiment. I'm so glad the seedling did not die-back this winter.

I expect its growth will really take off this year especially since it is growing on its own roots (not grafted).

Looking good! Thanks for the updates! .

Here's a little update on the little Keraji seedling, May 4, 2020.

It looks pretty much the same as it did in February, maybe the leaves have greened up just a little bit, but it's barely noticeable.

Many of the other hardy citrus have just started showing signs of beginning to put out little leaflet growth.

Here's the Yuzu seedling

growing very well now, lots of darker new leaves, and the old leaves look fairly healthy too.
I don't know how tall it is now but it's definitely more than 12 inches now and is beginning to fill out nicely.
May 21, 2020

• Are you trialing any thing other than yuzu, Ichangquat and keraji.
• Are you trialing one of each?

Yes, I am trialing several other things, which are discussed in other threads.

Keep in mind that even though I am so far north, this location is still classified as being in climate zone 8a.

I'm pretty sure none of these varieties discussed in this thread would be able to grow in your zone 6.

Im slowly getting my lemon seedling to grow again