Five Year Native Tree Challenge: Gabler's White Oak

[Gabler]

Just for fun, I'm gonna see if I can manage to air layer this Quercus alba "white oak tree."

 

[Gabler]

 

[Gabler]

 

[Gabler]

I recently determined I misidentified the tree this fall. It's a burr oak. Quercus macrocarpa. It fortunately still is native to my county in Maryland, according to the US Geological Survey. Note the little green dot on the Eastern Shore, just east of D.C.

 

[Leo in N E Illinois]

It is well documented that oaks are difficult to near impossible to get cuttings to root. But here on BNut I've seen a small number of oak air layers that actually were successful. I don't know "out of how many tries", but there is no reason to not try. Your local bur oak seems to be one with nice corky bark on fairly young branches. You should give it a try. Do not rush it. Put the air layers on in spring. Keep moist. If they have no roots by the end of summer, just cut flat the bottom edge of callus that formed, scrape clean any cambium trying to bridge the ring you cut and then re-wrap and keep the moss wet through the following winter spring & summer. It can take 2 years to get good enough roots.

You might get lucky, and get roots right away. But you might not. Just don't give up for at least 2 growing seasons.

 

[Gabler]

It is well documented that oaks are difficult to near impossible to get cuttings to root. But here on BNut I've seen a small number of oak air layers that actually were successful. I don't know "out of how many tries", but there is no reason to not try. Your local bur oak seems to be one with nice corky bark on fairly young branches. You should give it a try. Do not rush it. Put the air layers on in spring. Keep moist. If they have no roots by the end of summer, just cut flat the bottom edge of callus that formed, scrape clean any cambium trying to bridge the ring you cut and then re-wrap and keep the moss wet through the following winter spring & summer. It can take 2 years to get good enough roots.

You might get lucky, and get roots right away. But you might not. Just don't give up for at least 2 growing seasons.

Could it help to use a little bit of hormone powder, or would that do more harm than good?

 

[Gabler]

It is well documented that oaks are difficult to near impossible to get cuttings to root. But here on BNut I've seen a small number of oak air layers that actually were successful. I don't know "out of how many tries", but there is no reason to not try. Your local bur oak seems to be one with nice corky bark on fairly young branches. You should give it a try. Do not rush it. Put the air layers on in spring. Keep moist. If they have no roots by the end of summer, just cut flat the bottom edge of callus that formed, scrape clean any cambium trying to bridge the ring you cut and then re-wrap and keep the moss wet through the following winter spring & summer. It can take 2 years to get good enough roots.

You might get lucky, and get roots right away. But you might not. Just don't give up for at least 2 growing seasons.

Also, you're right about the corky bark. The whole tree is only three or four years old. Maybe eight feet tall?

 

[LittleDingus]

Could it help to use a little bit of hormone powder, or would that do more harm than good?

I've often wondered if some soil from the pot mixed into the air layer soil would help?? Some oaks are known to be mycorrhizae obligate. I've wondered if the fungal relationship would help encourage root growth after a callus has formed.

But then again, I've seen many oaks with branches that have buried themselves that I though should have layered naturally but haven't. But maybe those never had a callus to start roots from?

But, yes, I've seen just enough documented successes of layering oaks to think there may be some "trick" that can increase the odds. Unfortunately, I do not currently have access to any oaks to test some ideas out with

 

[Gabler]

I've often wondered if some soil from the pot mixed into the air layer soil would help?? Some oaks are known to be mycorrhizae obligate. I've wondered if the fungal relationship would help encourage root growth after a callus has formed.

But then again, I've seen many oaks with branches that have buried themselves that I though should have layered naturally but haven't. But maybe those never had a callus to start roots from?

But, yes, I've seen just enough documented successes of layering oaks to think there may be some "trick" that can increase the odds. Unfortunately, I do not currently have access to any oaks to test some ideas out with

What ideas would you test out? I'll try them on a few different oaks and report back to this thread for you. I like the soil and hormone ideas.

 

[LittleDingus]

Please don't do anything on my account...but I see no harm in it if you do...

One thing I want to try if I can find something acceptable to try it on is to mulch some of the leaves and mix in some soil from the paren and try to encourage mycorhyzal growth around the callus. What I was thinking was to make a standard air layer, let it callus, open the layer to score/reopen the callus then try to encourage mycorrhyza around the callus in the hopes that a symbiosis forms that encourages root growth. Crushed leaves from the parent should provide suitable organics and soil from around the parents should be a good innoculent for the preferred mycorr species.

This is pure speculation/wishful thinking on my part! I do have several oak species in pots. All but my gambel oaks have a tendency to grow mushrooms when it is cold and damp. I have bare rooted when repotting, but I've never "washed" the roots and am always careful to bring old soil into the new pot in the hopes of seeding new fungus. I haven't killed an oak repotting since I started doing that. I have a larger shingle oak I collected for this competition that I was also sure to carry soil forward for when potted. It may turn out to be a superstitious old wive's tall, but I've read sources that claim some oaks are mycorr obligate and, as long as my anecdotal evidence doesn't disagree, I see no harm in treating them that way...

 

[Gabler]

Please don't do anything on my account...but I see no harm in it if you do...

One thing I want to try if I can find something acceptable to try it on is to mulch some of the leaves and mix in some soil from the paren and try to encourage mycorhyzal growth around the callus. What I was thinking was to make a standard air layer, let it callus, open the layer to score/reopen the callus then try to encourage mycorrhyza around the callus in the hopes that a symbiosis forms that encourages root growth. Crushed leaves from the parent should provide suitable organics and soil from around the parents should be a good innoculent for the preferred mycorr species.

This is pure speculation/wishful thinking on my part! I do have several oak species in pots. All but my gambel oaks have a tendency to grow mushrooms when it is cold and damp. I have bare rooted when repotting, but I've never "washed" the roots and am always careful to bring old soil into the new pot in the hopes of seeding new fungus. I haven't killed an oak repotting since I started doing that. I have a larger shingle oak I collected for this competition that I was also sure to carry soil forward for when potted. It may turn out to be a superstitious old wive's tall, but I've read sources that claim some oaks are mycorr obligate and, as long as my anecdotal evidence doesn't disagree, I see no harm in treating them that way...

I like that idea. I'll definitely give it a try.

 

[Leo in N E Illinois]

@Gabler

Hormones - I have no definitive answer. A little can really help, too much will actually inhibit roots. I suggest you set up at least 3 air layer attempts on different branches. Use hormones in at least one. Use no hormones for at least one.

Rooting media. I have tried many things over the years. I strongly, and I do mean strongly recommend just using long fiber sphagnum moss, the Chilean import or New Zealand imported moss if you can get it. I DO NOT recommend adding soil. I do not recommend adding inoculum until AFTER the air layer is separated and is being established in on roots that have already formed.

Moss is much easier to keep moisture levels correct for rooting. You need consistent moisture for a full growing season, possibly a full 18 months. With potting media, pumice, whatever hanging in the tree you will have a difficult time keeping up on with it. With a moss bundle, you get the moisture right, it is well wrapped, you only need to check for moisture once a week or so. Much easier if you have to hike out to the trees.

Moss has antimicrobial properties, moss tends to inhibit disease. If your "inoculated bonsai potting mix" has any stray pathogens you will be creating problems, possibly terminal rots.

It is just fine, inoculating an oak AFTER the roots have formed. Prior to root formation, you are more likely to get pathogens instead of desired mycorrhiza.

But I have never air layered an oak. I've successfully air layered Malus, and JBP. and a few other species.

I very much recommend attempting more than one air layer. As air layers are never 100% successful. Vary different factors. Keep track of what works.

 

[LittleDingus]

@Gabler

I DO NOT recommend adding soil. I do not recommend adding inoculum until AFTER the air layer is separated and is being established in on roots that have already formed.

That's Leo's polite way of calling me a dumb ass

For the record, I strongly encourage others to follow Leo's advice. I even started my post with "Don't do anything on my account..."! But I was asked...so...

I have every intention of trying something like this myself. That's not an endorsment or argument that I am "right" or know anything about anything. I may have to buy a large nursery tree to try it on because I otherwise have no material I want. I've not been able to find a chinquapin in my local nurseries though...that's the one oak species I might be too impatient to just grow from acorns I do expect if I find one of the size I want, it will be grafted...every nursery oak here is grafted

So again...to be absolutely clear because this is the internet and everyone will accuse me of killing your trees: Do what @Leo in N E Illinois says...not what my dumb ass says!

 

[Leo in N E Illinois]

Sorry, I wanted to be clear, but I probably should have toned down my response.

Still friends?

 

[LittleDingus]

Sorry, I wanted to be clear, but I probably should have toned down my response.

Still friends?

Hehe...of coarse! Well digital acquaintances anyway

For the record, what I was suggesting is little more than a ground layer...I could write a book with all the things I don't do "by the book". Usually I just keep to myself about it...but I'm lucky enough to have been working remote for 9 months now while the rest of the family is still in person. I get pretty bored these days

 

[Gabler]

I have 120 acres of forest to work with, so I see no harm in experimenting with a variety of different techniques. I'll use the tried-and-true method on branches I really want, and I'll try the weird stuff on other branches for comparison. Worst case scenario, a few trees lose lower limbs, but if it works, I have a few trees to plant in the ground to expand the forest in addition to some bonsai material.

 

[Trenthany]

With a whopping two attempts on oak air layers I have 0% or 100% success rate. Lol. Nothing fancy just generous with hormones and a ball of sphagnum. Took 3 months to root to a solid ball just about lol. The only thing that I did that made me notice a difference was based on first attempt a couple years ago. I only got callous and white bump preroots. Since it still seemed healthy the next year I scraped the callous half heartedly and pretended I started them from scratch but by then I learned about foil because “light” is bad on the layer. Not sure about validity but I have hundreds of yards of foil. So I tried again with foil covering. Had roots within days and an untangleable mass in 3 months. I am not sure it’s “light” I think it’s temperature myself... Just a WAG but I’d like to research it. Foil has done miracles for my layering success.

 

[Sputnik 184]

Two successful air layers achieved on Quercus robur but both times the layer took two seasons. Each time the lower half of the callus was recut and bridging was removed.

 

[Trenthany]

Two successful air layers achieved on Quercus robur but both times the layer took two seasons. Each time the lower half of the callus was recut and bridging was removed.

Since both of our successful attempts match perhaps there is something to this as a theory. I have more oaks to take out around this age perhaps I should try again and being in FL I can probably do this in one season. I’ll try a set with and without foil. I’m hoping 3 months getting callous and next three roots then three months recovery before winter at max. As soon as my weekend from hell is over I will try and get my oak layers done.

 

[Gabler]

I'll post pictures later, but I went with foil to hold the moss, and I mixed in rooting hormone powder with the water that I used to wet the moss, so it should be present in all the layers in a low concentration.