Rule of thumb for root reduction of Hornbeams?

[Scrogdor]

Lifted my American Hornbeam out of its original 3gal nursing pot and the root mass is ultra dense with several large deep roots that go down about 6". Guessing I'm going to have to saw off the bottom portion of it and slowly reduce it over a number of seasons? What's a good rule of thumb for how much to reduce the root mass by?

 

[leatherback]

If your tree is healthy I would not worry about it and just reduce to a size suitable for the next container. 6 inches is nothing.
With deciduous in early phases, I regularly remove 80% of the roots. But be smart about it. Just lopping of a part of the roots and putting it in a pot is not going to help. Try to remove the old substrate so that the roots are an untagled wig. Then reduce the roots to length and where possible, clip big roots back to a side-roots. This way you can steer root development, encourage weak roots and hold back strong roots.

When growing in pure organic nursery trade muck you sometimes do not have a real option but to saw off a section of the rootball. But after that initial cleanout I prefer to take things a little more gentle and carefully look at the roots.

 

[Shibui]

Hornbeam seem to be comfortable with quite extreme root reduction. 80% has been fine for the ones I work with too.

With commercial stock make sure you identify where good upper roots join the trunk. Often the small seedlings are potted deep so sawing blindly through the root ball can result in roots in one part and trunk with no roots in the other.

 

[Scrogdor]

Hornbeam seem to be comfortable with quite extreme root reduction. 80% has been fine for the ones I work with too.

With commercial stock make sure you identify where good upper roots join the trunk. Often the small seedlings are potted deep so sawing blindly through the root ball can result in roots in one part and trunk with no roots in the other.

The trunk is about 1.5 inches thick on this. Root mass is probably greater than the tree by 2x. It has 3 long radial roots at the top, then the tap root extends down a bit narrows and then it branches into several more thick roots. Most of the feeder/fine roots are in this huge mass of roots and not near the top. Forgive this crude picture, The blue lines is where I'd like to chop but there are no feeders above those lines.

 

[Shibui]

Retaining feeder roots is not necessary for many trees. New roots will usually grow quickly from the cut ends of hornbeam roots in spring.
Remember that a piece of branch can stay alive long enough to grow new roots and survive. Roots can grow new roots much easier and quicker than above ground cuttings so feeder roots are not necessary for many deciduous species. I would not advise chopping roots like this on conifers though.
Your virt is just what I would do in such a situation.

 

[rockm]

Carolina (American) Hornbeam can take drastic root reduction. Collecting them here, I don't dig them up, as much as saw them out of the ground. When I've collected them from the wood, I have routinely sawed off 99 percent of feeder roots, severing all major roots four to six inches out from the trunk.

The containerized version of this would be to retain a few feeders, if possible, but it's probably not necessary if this tree is growing well. I'd saw off at the blue lines, I'd also chop the trunk at the same time to within three inches longer than the planned finished height.

I'd then wash all the old soil off with a hose, then plant securely (wire in) in a bonsai pot with bonsai soil. Put the tree where it's protected from wind (and frost if you get it, insuring you cover the nebari with at least an inch of soil. Also make sure the soil doesn't go dry and WAIT. Could take a couple of weeks before you see buds on the trunk.

 

[WavyGaby]

Carolina (American) Hornbeam can take drastic root reduction. Collecting them here, I don't dig them up, as much as saw them out of the ground. When I've collected them from the wood, I have routinely sawed off 99 percent of feeder roots, severing all major roots four to six inches out from the trunk.

The containerized version of this would be to retain a few feeders, if possible, but it's probably not necessary if this tree is growing well. I'd saw off at the blue lines, I'd also chop the trunk at the same time to within three inches longer than the planned finished height.

I'd then wash all the old soil off with a hose, then plant securely (wire in) in a bonsai pot with bonsai soil. Put the tree where it's protected from wind (and frost if you get it, insuring you cover the nebari with at least an inch of soil. Also make sure the soil doesn't go dry and WAIT. Could take a couple of weeks before you see buds on the trunk.

Thanks for the input. I just collected 2x american hornbeams and I was about to ask this same question, however, my damage was already done.
This is how aggressive I went on the larger Hornbeam. I cut off more than I expected because there is a concave area on the bottom, directly below the trunk that worried me. The concave area worried me bc it could cause a pocket of air and subsequent root rot if left as a void. Therfore, I tried cutting of adjacent roots to get the concave area flatter and even with the lateral roots.
I am keeping this one in the garage until early spring.
Total height is 16", smaller trunk is 10".

 

[rockm]

Thanks for the input. I just collected 2x american hornbeams and I was about to ask this same question, however, my damage was already done.
This is how aggressive I went on the larger Hornbeam. I cut off more than I expected because there is a concave area on the bottom, directly below the trunk that worried me. The concave area worried me bc it could cause a pocket of air and subsequent root rot if left as a void. Therfore, I tried cutting of adjacent roots to get the concave area flatter and even with the lateral roots.
I am keeping this one in the garage until early spring.
Total height is 16", smaller trunk is 10".

FWIW, I don't collect until the beginning/mid March. Too early and you risk die back. Good luck!

 

[leatherback]

The concave area worried me bc it could cause a pocket of air and subsequent root rot if left as a void.

This I very much doubt.

 

[rockm]

Thanks for the input. I just collected 2x american hornbeams and I was about to ask this same question, however, my damage was already done.
This is how aggressive I went on the larger Hornbeam. I cut off more than I expected because there is a concave area on the bottom, directly below the trunk that worried me. The concave area worried me bc it could cause a pocket of air and subsequent root rot if left as a void. Therfore, I tried cutting of adjacent roots to get the concave area flatter and even with the lateral roots.
I am keeping this one in the garage until early spring.
Total height is 16", smaller trunk is 10".

Sorry, meant to add to my post above...This is pretty much what I do when collecting hornbeam. Concave areas under the trunk are not all that much of a problem IF you work soil under the tree while you repot it. Flatter is better though, and it pays to flatten from the beginning.

This is a pretty decent tree. As I said, it's a bit early to collect this species for me at least.

 

[WavyGaby]

Sorry, meant to add to my post above...This is pretty much what I do when collecting hornbeam. Concave areas under the trunk are not all that much of a problem IF you work soil under the tree while you repot it. Flatter is better though, and it pays to flatten from the beginning.

This is a pretty decent tree. As I said, it's a bit early to collect this species for me at least.

Thank you. I am excited for its potential. I was so excited that I used my APL mix on this instead of the cheap organic mix I've put collected material with in the past. I think this will reduce the risk of a void, as well.

 

[WavyGaby]

This I very much doubt.

I had a problem a couple of years ago with some American Elms I collected. I used organic potting soil with perlite that time. I know this is anecdotal and not enough evidence, however, one Elm took off in the spring, the other stalled. The one that stalled clearly had a similar void below the trunk that I didn't notice initially. The tree never made it. I think it was likely the combination of the soil and lack of packing that created the void and caused rot.

I used APL this time, packed as best as possible, so I think this material will have a better chance at filling and voids

 

[Brian Van Fleet]

Thanks for the input. I just collected 2x american hornbeams and I was about to ask this same question, however, my damage was already done.
This is how aggressive I went on the larger Hornbeam. I cut off more than I expected because there is a concave area on the bottom, directly below the trunk that worried me. The concave area worried me bc it could cause a pocket of air and subsequent root rot if left as a void. Therfore, I tried cutting of adjacent roots to get the concave area flatter and even with the lateral roots.
I am keeping this one in the garage until early spring.
Total height is 16", smaller trunk is 10".

I don’t see how this one makes it.

 

[WavyGaby]

I left more roots on this one

 

[WavyGaby]

I don’t see how this one makes it.

I am worried, but I hope I can prove you wrong.
After the work was done, I realized that I was treating it more like a trident maple with the aggressiveness I've seen others implement with those. I got caught up dealing with a potential void and admittedly got carried away. I am hoping the small side root with some fine hairs will help too.

 

[Brian Van Fleet]

I left more roots on this one

Those roots aren’t feeder roots at this point, they’re anchor roots. Trees really need to have some fine feeder roots to take up water into the tree. That’s what makes collecting a challenge. You might get lucky and the tree can issue new roots on stored reserves, but more likely those stored reserves will produce weak foliage growth, which will die because no roots are supplying the new growth with moisture. Worse, doing this in the middle of winter means the tree won’t have any growth signals (day length or warmth) for another 6-8 weeks.

If you’re going to be this aggressive with root removal, it needs to happen when the tree is starting to grow and can respond with growth.

I wish you luck, that first hornbeam has potential.

 

[rockm]

Those roots aren’t feeder roots at this point, they’re anchor roots. Trees really need to have some fine feeder roots to take up water into the tree. That’s what makes collecting a challenge. You might get lucky and the tree can issue new roots on stored reserves, but more likely those stored reserves will produce weak foliage growth, which will die because no roots are supplying the new growth with moisture. Worse, doing this in the middle of winter means the tree won’t have any growth signals (day length or warmth) for another 6-8 weeks.

If you’re going to be this aggressive with root removal, it needs to happen when the tree is starting to grow and can respond with growth.

I wish you luck, that first hornbeam has potential.

"If you’re going to be this aggressive with root removal, it needs to happen when the tree is starting to grow and can respond with growth."

Agree That's why I mentioned it's a bit early for collection. Collecting while the tree is completely dormant can be a problem as you remove roots that store some of the tree's resources it has yet to draw on. Early spring is best for this species, as buds swell and are just about to open is optimal.

Also, I assume "APL" is akadama, pumice and lava...That might be too lean for a hornbeam. Hornbeam is a bottomland species, growing in very moist environments along streams and flood prone areas of rivers. I've always added 1/3 granular organics (sifted composted pine bark, "fine" grade orchid soil) to the soil I use with collected hornbeam.

 

[penumbra]

Great thread for all of us. Thank you.

 

[Brian Van Fleet]

Also, I assume "APL" is akadama, pumice and lava...That might be too lean for a hornbeam. Hornbeam is a bottomland species, growing in very moist environments along streams and flood prone areas of rivers. I've always added 1/3 granular organics (sifted composted pine bark, "fine" grade orchid soil) to the soil I use with collected hornbeam.

Yes, at the least I would recommend a heavy layer of sphagnum moss on the top of the soil to hold in moisture at this point, and protect them from freezing.

 

[WavyGaby]

Those roots aren’t feeder roots at this point, they’re anchor roots. Trees really need to have some fine feeder roots to take up water into the tree. That’s what makes collecting a challenge. You might get lucky and the tree can issue new roots on stored reserves, but more likely those stored reserves will produce weak foliage growth, which will die because no roots are supplying the new growth with moisture. Worse, doing this in the middle of winter means the tree won’t have any growth signals (day length or warmth) for another 6-8 weeks.

If you’re going to be this aggressive with root removal, it needs to happen when the tree is starting to grow and can respond with growth.

I wish you luck, that first hornbeam has potential.

Thank you!