[Dingus] Cork oak (quercus suber)

[LittleDingus]

In late 2018, I sprouted a bunch of cork oaks. I started with ~30 acorns hoping to get 2-3 through the winter to play around with. 28 of them germinated and survived the first winter! Despite my many abuses and almost complete disregard for the calendar, I still have over 20 of them just growing away. I only remember 2 dying for sure but I only counted 21 when I walked around counting them just now so I may have lost track of a grow bag or two somewhere. Most of them are growing in community grow bags of 3-5 trees each and are currently scattered in several locations: my basement, the garage, a few testing how much cold they can survive through outside, etc...

Anyway, I just purchased this sweet pot from @sorce! (Thanks again Sorce!)



I bought that pot specifically for a cork oak. I ultimately want something with a bigger trunk in there, but, while the others continue to grow out more, I picked one that happened to be planted by itself to keep the pot warm

I didn't take a before pick until after I got it out of the grow bag I did get a picture of the roots straight out of the grow bag though:



Lots of fibrous roots and lots of healthy white growth tips! This guy has been kept in my garage under grow lights since November. It's been averaging 50F-55F where this tree sits. Maybe as low as 45F on cold nights.

I've trimmed the tab root back some on this one back at the end of 2019, but it was still about 4" long. I needed to trim ~2" off it to get the tree into the pot. It will need further trimming at the next repot but I was starting to loose more root ball than I was comfortable with given that it's still the middle of winter here.

Here's where I ended:



Lots of fibrous roots left, but most of the live growth tips were in the bottom part of the ball that I cut off Really warm weather is still a few months off. This guy will go back into the garage for now so will hopefully have some time to grow back some live tips before the heat starts up in earnest!

Here it is with the new shoes:



It's more centered than I had hoped. I wanted it shifted left about an inch, but I would have had to cut off more root to get it over there...sigh...next time!

I trimmed back to a profile and added a bit of wire. I'm not a big "wire" guy...I don't use it but hardly at all. But I did want to move the two main branches on the mother trunk to fill in a little better canopy profile for now.



Still a long way to go! But pleasing enough for an oak that's not yet 3 years old

I like the "mother/daughter" look, but I almost went with a different front. There's a bit of shari on the daughter side of the mother trunk that I like that I almost used as the front.



It puts the daughter a little more to the front though...which I didn't care for. I expect that it will close up in a year or two anyway...I may even rough up the callous edges in the spring to help it close so that there's not much scar when/if this guy gets old enough to start corking.

This little guy will always be outclassed by the real bonsai of the world, but it's fun to play with! How does that commercial go??

Acorn: $0.25
Grow bag: $2.00
NAPA 8822: $2.00
Bonsai pot: $85.00
Having to water, trim, and otherwise care for a stick in a pot: priceless!

 

[luvinthemountains]

Great work! A word to the wise - the branches on my older cork oak seem to get stiff quickly when lignifying. You may hate to wire, but this may be your only chance to get some movement in those branches. As-is, the tree is pretty but with many upward facing, straight branches the image is of a young tree. Just my two cents.

I wonder how your experience has been with the trees left outside. My tree got very unhappy back in December when the temps dropped into the low teens with a lot of wind. I am afraid there will have been a lot of dieback. Not that it matters, though. This one is scheduled for a hard pruning this year, and next year will hopefully have a greenhouse to go into.

 

[LittleDingus]

Great work! A word to the wise - the branches on my older cork oak seem to get stiff quickly when lignifying. You may hate to wire, but this may be your only chance to get some movement in those branches. As-is, the tree is pretty but with many upward facing, straight branches the image is of a young tree. Just my two cents.

I wonder how your experience has been with the trees left outside. My tree got very unhappy back in December when the temps dropped into the low teens with a lot of wind. I am afraid there will have been a lot of dieback. Not that it matters, though. This one is scheduled for a hard pruning this year, and next year will hopefully have a greenhouse to go into.

Thanks for the warning on lignification! I think that's pretty much true for all oaks. My virginiana are also 2 years old and they are even stiffer than these are!

I'm not worried about young tree/old tree images. This guy is really just keeping the pot warm for now. I've started moving some of my multitudes of trees in grow bags into nicer pots so I can place them about the deck and be less of an eye sore. I don't mind the look of the bags myself, but they are a bit tacky. I'm also curious how little it will thicken up compared to it's brethren still in much larger grow volumes

My plan, at the moment, is to leave this one in this pot until it needs to be repotted again, probably in 2 years. That'll be 2 years additional growth on some of its siblings that are less restricted. When it's time to repot, I'll swap this one out for one with, hopefully, a bigger trunk That could all change depending on how this one develops...for me, it's more about the journey than the destination

I've been surprised what these guys can take outside! Last winter I left them outside through much of December and only brought them in for the coldest few weeks of winter. I got lazy bringing them in and the runt of the litter got left outside for the entire winter. I don't recall how cold we got last winter, but that tree survived! I kept track of it and left it outside again this winter on purpose to test it again.

It's near the house and in a spot that's mostly out of the wind. We had a high of 9F today. The past two days have been single digit lows. We're predicted to get to -13F Saturday night. Predicted highs for the next week barely reach the low teens. This will be a bit of a test! It's under a dusting of snow now.



It is definitely smaller than all the others from the same set of acorns, but it was the runt to begin with so I can't say that the winters are what set it back. It's hard to tell when they are dormant, but it's still pliable and feels healthy to me. We'll see!

 

[Matte91]

How many years do you think it will take, before the trees are developing cork bark?
I got some of them too

 

[LittleDingus]

This pot was purchased from sorce through:

Pots — All Sorts Sorce Arts

www.allsortssorcearts.com

I ordered 2 pots and the order came with a super-mini pot as a bonus!

I've bought pots from sorce in the past when he held auctions in the sales forum. One of those previous purchases came with a little sprig of sedum. I tossed the sedum into a pot thinking I would move it somewhere more appropriate at some point...but forgot...and now that pot is half full of sedum! So I took a clipping and the super-mini pot and put together this silly little display for this tree.

So, here it is: Quercus Suber in a Sorce pot accented with a sprig of sedum also in a sorce pot



This how I killed my afternoon while waiting for the fixer man to come fix my busted furnace

 

[luvinthemountains]

I'm also curious how little it will thicken up compared to it's brethren still in much larger grow volumes

Me, too. I would also be curious whether the smaller container helps to shorten the internodes - especially when the roots have fully colonized the pot and start to be constrained.

 

[Bonds Guy]

Funny how this is the first post I seen after considering to get one of these come spring. Do you know how cold hardy they are? Winters here can brutal and I don’t really have space to protect it from frost.

 

[LittleDingus]

How many years do you think it will take, before the trees are developing cork bark?
I got some of them too View attachment 353192

My understanding is that they are making cork bark immediately. That is, what we think of as "cork bark" is not any different than the bark they make as the new growth hardens off. Just that at some point, enough of it has accumulated with nowhere to go that it starts to look twisty and swirly and craggy and such.

Basically, as the tree makes new bark underneath the old, it pushes the old bark out. As that happens, the outer bark fissures and splits because it can no longer stretch enough to stay intact. Over time, this causes the thick, interesting bark we grow these things for

I don't know how long it takes that process to get to the point where they look "corky". I've read as little as 3-5 years. I've also read the first cork harvest is typically at 25 years then roughly every 10 thereafter.

For best/quickest corking, I think you want the same thing as what thickens trunks...lots of vigorous growth!

FYI: I cut the apex off some of mine before as tall as yours. That had the effect of creating a much bushier tree with more growth lower down.



I'm not suggesting you do that with yours. I'm just showing you potential results if you do. I did leave some grow tall. I'm not sure I notice much difference in average trunk thickness yet (too soon to tell, really) but I do find the shorter trees easier for me to manage in my situation

 

[LittleDingus]

Me, too. I would also be curious whether the smaller container helps to shorten the internodes - especially when the roots have fully colonized the pot and start to be constrained.

My general experience with oaks is that internode spacing and leaf size has a stronger correlation to light intensity than container size. As an example, these leaves all came off this tree during this pruning. The larger ones are from growth last winter/early spring when the tree was under lights. The smaller ones are from the summer flush when the tree was outside.



I have a couple I keep in a bright south-east window indoors over the winter. Those are warm enough that they pushed a small flush of growth in December. Those leaves are much larger than average with longer internodes as well.

If you have the opportunity to walk through an old growth oak forest, you'll notice the younger understory trees and even the lower, more shaded branches of older trees will have leaves that are significantly larger than the upper canopy.

 

[LittleDingus]

Funny how this is the first post I seen after considering to get one of these come spring. Do you know how cold hardy they are? Winters here can brutal and I don’t really have space to protect it from frost.

I winter most of mine in the garage where they stay above 40F most of the time. I mentioned above that last winter I "forgot" one outside and was surprised it survived the winter here in zone 6a. Last winter was pretty mild for us...but I do recall a week or so of single digit temps.

The big test is I left that same tree outside this winter. We had a low of 5F overnight. Predicted lows of -13F by the weekend.

My experience is most trees I've had die over the winter die of dehydration. If you can keep the tree out of the drying winds, that helps a LOT. I'm not sure how long the root ball on these can stay frozen solid though. If the roots are frozen, they can't draw moisture into the leaves. Constant freeze/thaw cycles are bad too

Sorry, not much help! No real answers for you...just one data point from one sorry little tree

 

[Matte91]

My understanding is that they are making cork bark immediately. That is, what we think of as "cork bark" is not any different than the bark they make as the new growth hardens off. Just that at some point, enough of it has accumulated with nowhere to go that it starts to look twisty and swirly and craggy and such.

Basically, as the tree makes new bark underneath the old, it pushes the old bark out. As that happens, the outer bark fissures and splits because it can no longer stretch enough to stay intact. Over time, this causes the thick, interesting bark we grow these things for

I don't know how long it takes that process to get to the point where they look "corky". I've read as little as 3-5 years. I've also read the first cork harvest is typically at 25 years then roughly every 10 thereafter.

For best/quickest corking, I think you want the same thing as what thickens trunks...lots of vigorous growth!

FYI: I cut the apex off some of mine before as tall as yours. That had the effect of creating a much bushier tree with more growth lower down.

View attachment 353201 View attachment 353200

I'm not suggesting you do that with yours. I'm just showing you potential results if you do. I did leave some grow tall. I'm not sure I notice much difference in average trunk thickness yet (too soon to tell, really) but I do find the shorter trees easier for me to manage in my situation

Thank you for some good explanations
I have a couple of these oaks, my plan is to plant one of them in the ground and let it grow for some years, and my plan for the other one is to cut the apex as you did. Good luck with yours

 

[Potawatomi13]

Funny how this is the first post I seen after considering to get one of these come spring. Do you know how cold hardy they are? Winters here can brutal and I don’t really have space to protect it from frost.

Zone 8 if memory serves. Single digits and below makes likely dead tree.

 

[LittleDingus]

Zone 8 if memory serves. Single digits and below makes likely dead tree.

Last winter I left one outside all winter here in 6b by "accident". Actually, I ran out of room and was too tired of moving pots around and I had way more than enough of these for my needs, so it sat outside all winter...and lived! This is the one I mention above somewhere.

I left the same tree outside all wither this year as well...just to see. The test was a bit unfair. We had a freak cold snap that didn't climb above 0F here for several days straight. One night hit -15F. I had brought most my other hardy natives into the garage for that cold snap. I did not bring this one in. The leaves turned a lovely grey color: they look and felt freeze dried!

So my sample size of 1 says they can survive somewhere between a warmish and a stupid coldish zone 6b winter...yeah, not much help

In practical terms, the part of the equation that doesn't get much discussion is duration. A number of mine have survived a day or two of freezing temps. The week that never got above 0F, some of the ones I had in the garage were close enough to the outside door/wall that they dipped below freezing for a bit. I suspect they can survive a light freeze or two if the duration is short enough.

 

[jquast]

Last winter I left one outside all winter here in 6b by "accident". Actually, I ran out of room and was too tired of moving pots around and I had way more than enough of these for my needs, so it sat outside all winter...and lived! This is the one I mention above somewhere.

I left the same tree outside all wither this year as well...just to see. The test was a bit unfair. We had a freak cold snap that didn't climb above 0F here for several days straight. One night hit -15F. I had brought most my other hardy natives into the garage for that cold snap. I did not bring this one in. The leaves turned a lovely grey color: they look and felt freeze dried!

So my sample size of 1 says they can survive somewhere between a warmish and a stupid coldish zone 6b winter...yeah, not much help

In practical terms, the part of the equation that doesn't get much discussion is duration. A number of mine have survived a day or two of freezing temps. The week that never got above 0F, some of the ones I had in the garage were close enough to the outside door/wall that they dipped below freezing for a bit. I suspect they can survive a light freeze or two if the duration is short enough.

Cork oaks are endemic to mediterranean regions and do not like cold snaps. You should see one of Walter Pall's really nice Cork oaks that lost most of its branches due to a cold snap and set it back several years. I have more than a few nice cork oaks that I'm careful with and bring in if we should get a cold snap of more than a few days.

The cork bark oak catastrophy

Cork bark oak, Quercus suber. first iamge last summer. In October I had the tree in the greenhose. Over night we had just a bit of frost and...

walter-pall-bonsai.blogspot.com

 

[LittleDingus]

But anyway...time to kill another tree!

Todays candidate is this lucky stick-in-a-bag!



Why this tree? Welp, I've hit the point in the year where it's too warm in the basement for me to manage my watering schedule down there well enough for the rainbow eucs. That means it's time for them to move outside where I have a hose handy. And, since my trees keep getting bigger, they don't currently fit anywhere unless I downsize something else. I have a number of cork oak growing out at the moment...too many for my needs. This lucky stick is potted all by itself and was sitting where I wanted to put a rainbow euc so, it volunteered

I yanked it out of the grow bag



and hacked at it until it fit in the pot I had available



I took off enough root to go from a 1 gallon grow bag to a shohin sized pot! I very well have have killed this one...sigh. But, the only way I could avoid something more than a few branches going onto the compost pile at this time was to move this guy into a tiny pot and wish it well. After the severe root prune and some cutbacks up top to help reduce water needs, I did get it into a pot.



and now the canopy is small enough I can fit it into a different spot where it will be safe from future culling...well, if it survives

Honestly? I don't think I've killed it. I've certainly set it back a bit...but I wouldn't have wasted the time to wire it into a pot if I legit thought I killed it. I left some of the new growth, but I'm guessing that will all die off, though. There should be enough existing foliage to provide energy to flush again...it may just take a few weeks. Not all the swelling buds from this flush had popped so maybe it can come back a little quicker.

I've yet to move my baobabs outside so perhaps I'll be killing a few more trees next weekend! The next round is likely to be from my southern live oaks!

At least so far I'm only killing off my "extras" I still have about 15 cork oak and maybe a dozen southern live oak growing out that are at risk of future culling From here out, I think I'm more likely to cull southern live oaks. The corkers have much more interesting trunks so I want to keep them as long as I can to see how they develop.

 

[LittleDingus]

Cork oaks are endemic to mediterranean regions and do not like cold snaps. You should see one of Walter Pall's really nice Cork oaks that lost most of its branches due to a cold snap and set it back several years. I have more than a few nice cork oaks that I'm careful with and bring in if we should get a cold snap of more than a few days.

The cork bark oak catastrophy

Cork bark oak, Quercus suber. first iamge last summer. In October I had the tree in the greenhose. Over night we had just a bit of frost and...

walter-pall-bonsai.blogspot.com

Mine winter either under lights in my garage or in a very bright wall of windows in my basement. I've only played with a few of them (well, mostly just that one) in the cold to see what they do. I'm looking to move another zone colder in a year or so. In practice, all the cork oak I have that I care about are adaquately protected from the weather This report was mostly to tie up an earlier conversation in the thread.

I planted 30 acorns a couple years ago hoping for 3-4 trees, but they mostly all germinated and now the bigger they get, the bigger my space issues become. So I can deal with killing off a few

 

[LittleDingus]

Wow! It's been 2 months now since I made this bold statement!

But anyway...time to kill another tree!

...

View attachment 372118 View attachment 372113

...

Honestly? I don't think I've killed it. I've certainly set it back a bit...but I wouldn't have wasted the time to wire it into a pot if I legit thought I killed it. I left some of the new growth, but I'm guessing that will all die off, though. There should be enough existing foliage to provide energy to flush again...it may just take a few weeks. Not all the swelling buds from this flush had popped so maybe it can come back a little quicker.

...

It DID make me a little nervous...



...but: life!



Still an upward climb though. July can be a hot month! Thankfully my workplace has said the earliest they'd bring us back onto campus is October. That makes it much easier to keep an eye on these guys during the afternoon heat

 

[LittleDingus]

I tend to lump all my trees from the same species into a single thread...probably I should stop doing that?? I guess mostly I do it when I don't think of the trees as individual "bonsai" yet...just easier to track on a single thread of crappy work than have to find a specific thread for a specific crappy tree

This one, I'm really liking, however. It might become worthy of it's own thread if I can get it to fill in more.



That's a horribly picture...I've been poking through all my trees after a solid week of daily rains and I'm too lazy to stage every tree for a better pic right now. But I do really like how this one is shaping up for the size of trunk it has.

It is also flushing new growth...



The growth is out at the edges. It needs some hard cutbacks to fill in how I'd like. This will be it's second full flush since going into this pot. If it flushes well, I might try and time the next flush and do a harder chop to push back some growth.

Or maybe I just worry about it in the spring...