Root pruning American Hornbeam

[pweifan]

How aggressively can you prune the roots of an American Hornbeam?

Last year I collected an American Hornbeam from my parent's property in MI. It's been growing in a large growbox since then. Today, I've been repotting the other trees I collected and since they all have small rootballs, I put them in pond baskets. However, the tree I'm asking about has a shallow, but very wide rootball. I made a 11"x11" growbox to put it in, but the roots are still too wide. There aren't a lot of fine roots close to the trunk, so I was afraid to cut too aggressively. Am I being paranoid, or should I keep it in the larger growbox and cut half the roots for the next 2 years?

I ran out of light, so I didn't take any pictures but OMG is the nebari on this tree amazing. I really don't want to ruin it.

Thanks!
Scott

 

[Handsome John]

Depending on how thick the roots are, just take it slow and clip it back slowly, i treat hornbeams like i do Japanese maples so no big rush because the finished product outweighs the risk of killing or hurting the tree plus you can refine the branches while you work the roots each season! For this though i would maybe recommend just chopping one or two large roots and adding root hormone to try and chase it closer and just do that each year, then again thats just me

also lets see some pics! (see if the roots live up to the hype haha)

 

[augustine]

It's a collected tree, one year in a container and a slow growing species. Prune very conservatively and let it get strong. Reduce rootball over a number of years.

Think leaving it in the new large box for at least 2 years to let it get strong, no need to report every year. I know what you mean, we collect these beautiful hornbeams and they look ready for a display container BUT it's still bonsai and takes years to develop a deciduous tree.

 

[rockm]

Here's how I collect American Hornbeam--FWIW, being timid with them usually kills them.

I find a larger tree --trunk up to seven or eight inches are fine--smaller ones can be ok, but they're rarely worth the effort. I measure out about six inches from the trunk, dig down six inches with a hand trowel and start sawing off major roots all the way around the trunk. I leave the top on the tree to use as a lever to push the rootball up to sever all the big roots underneath. I pull the tree out of the ground, do a rough reduction cut on the top, take it home in a wet towel or plastic bag. When I get it home, I wash off ALL the old soil. Clean up the root cuts with a sharp cutter or knife to produce clean edges on the cut, then plunk it into the shallowest, smallest container I can get the rootmass into. Backfill with regular bonsai soil. Put it in the shade for a month.

I've done this for over a dozen Carolina hornbeam. The only one I've lost was a big one I left sitting on the ground in its container. It got caught in a heavy rainstorm a month after I collected it and had ground soil wash into its pot it carrying some kind of funky infection.

Notice I don't baby trees leaving soil on the root mass, or opt for a larger container. Both of those things can wind up killing the plant. Old soil is usually mud or some kind of muck, since hornbeam grow in damp and wet areas. It's not good in a container. It gums things up pretty quickly.

Smaller containers are better to newly collected trees than overly large ones. The soil mass is smaller and won't retain too much water. A container that's too large will remain constantly wet where the tree hasn't pushed roots. That constantly wet soil will wind up discouraging new root growth into it. Also you will add to this problem if you don't know it exists by overwatering the plant.

 

[jeanluc83]

Here's how I collect American Hornbeam

Do you seal your chop and how is your back budding on the trunk?

I collected some a couple of years ago. One never leafed out after collection. One went fairly good for a year then died. The third just grew some suckers from the base. It is still alive but only the suckers remain.

 

[rockm]

Seal the top chop and any other major wounds. Important point. Substantial winter protection (deep mulch and covered structure or cold pit) is also necessary the year after collection, and probably for the rest of its life. I've found this species to be kind of sensitive to colder temps once it's out of the ground even in its native range.

Hard winters with minimal protection can result in a dead tree years after it's dug, or significant dieback.

 

[Zach Smith]

What Mark said. I'll add that for any deciduous tree you collect, the roots can be cut back far harder than you might think. In fact, the same rule applies to chopping roots as to chopping trunk and any branches you may want to keep: you want taper, so cut the roots two to three (max) basal diameters from the trunk. When they regrow, almost always only from the chopped ends, you will build taper in the roots which is just what you want. The idea of slowly, gradually chopping back roots so as to successfully collect the tree is not only unnecessary, it causes a lot of remedial work down the road when you find out you have no taper in the nebari.

It's also a myth that you need fibrous roots when collecting (deciduous) trees. You don't. If you get some, fine, if you don't it's not a big deal. The tree wants to live, so it produces both adventitious buds and adventitious roots which are the moisture absorbing fibrous roots you need and want.

Zach

 

[pweifan]

Thanks for all the replies.

I basically did everything rockm (Mark?) said I shouldn't do when I collected it Kept a big rootball, didn't remove much of the original muddy soil and put it in a large container. This weekend I'll put on my big boy pants and get braver about cutting the roots.

I'll take before and after pictures . It's probably not to the quality you guys are used to working with, but I love the trunk and nebari. It's the first tree I ever collected, so the chop was done horribly and too high on the trunk. I'll ask for advice on where to chop it and how to prevent dieback.

Thanks again!
Scott

 

[rockm]

Thanks for all the replies.

I basically did everything rockm (Mark?) said I shouldn't do when I collected it Kept a big rootball, didn't remove much of the original muddy soil and put it in a large container. This weekend I'll put on my big boy pants and get braver about cutting the roots.

I'll take before and after pictures . It's probably not to the quality you guys are used to working with, but I love the trunk and nebari. It's the first tree I ever collected, so the chop was done horribly and too high on the trunk. I'll ask for advice on where to chop it and how to prevent dieback.

Thanks again!
Scott

You've done something right that most new collectors (and even those that have collected a few trees) get wrong--A trunk chop that's too high is VASTLY better than a trunk chop that's too low. You can always take more off. Leaving more trunk initially allows a better selection of apex buds to develop.

 

[rockm]

What Mark said. I'll add that for any deciduous tree you collect, the roots can be cut back far harder than you might think. In fact, the same rule applies to chopping roots as to chopping trunk and any branches you may want to keep: you want taper, so cut the roots two to three (max) basal diameters from the trunk. When they regrow, almost always only from the chopped ends, you will build taper in the roots which is just what you want. The idea of slowly, gradually chopping back roots so as to successfully collect the tree is not only unnecessary, it causes a lot of remedial work down the road when you find out you have no taper in the nebari.

It's also a myth that you need fibrous roots when collecting (deciduous) trees. You don't. If you get some, fine, if you don't it's not a big deal. The tree wants to live, so it produces both adventitious buds and adventitious roots which are the moisture absorbing fibrous roots you need and want.

Zach

I remember when bonsai sites were just beginning on the web and people were first posting pics. Some guy proudly posted a picture of the Carolina Hornbeam he had used a firehose to collect. He basically blasted all the soil off the entire root mass of the tree WHILE IT WAS IN THE GROUND. The tangled mess in the photo was about five feet tall and five feet across. He got all upset when he was told that he only really needed the first six inches of the roots out from the trunk. He got even more upset when he was asked how he was going to get it into a pot.

FWIW, I bareroot about 95 percent of all deciduous stuff I collect.

 

[Waltron]

here is one I collected the other day, how'd I do?

 

[pweifan]

"triplecrown's images are not publicly available."

EDIT: I see the pics now.

 

[Waltron]

made a ghetto green house out of old windows. dont hate. been windy as hell lately. they are goin in the garage for the next couple nights but it should be smooth sailing after that. hopefully.

 

[Waltron]

here is another one i collected recently, it is also in a ghetto green house, with the good ol log wind blocker.

 

[rockm]

First one is OK. I would have shortened those big roots more and used a smaller container. For a tree that size, a nursery five gallon plastic pot is fine. You have to remember to remove enough of the root mass to allow for the TOP of the nebari to be buried at least three inches, preferably more. Keeping the nebari from drying out is very important as it can lead to the death of the tree. Also, your soil looks to be on the lean, coarse side...

Second one I wouldn't have collected. Not enough going on there to make it worth keeping. Edit--didn't mean that the way it sounded. I should have said it's not enough to make ME think it's worth keeping. I have large and very large trees whose features are obvious. The second tree you posted has some potential as a shohin from what I can see. It still needs a substantial trunk reduction, like more than two thirds.

 

[Zach Smith]

First one is OK. I would have shortened those big roots more and used a smaller container. For a tree that size, a nursery five gallon plastic pot is fine. You have to remember to remove enough of the root mass to allow for the TOP of the nebari to be buried at least three inches, preferably more. Keeping the nebari from drying out is very important as it can lead to the death of the tree. Also, your soil looks to be on the lean, coarse side...

Second one I wouldn't have collected. Not enough going on there to make it worth keeping.

Great point about not allowing the nebari to dry out. When you collect lots and lots of trees over lots of years you stop thinking about the specific things you do to ensure survival. I do most of my collecting hours from home base. I actually bring with me tubs or large pots full of nursery mix and heel in everything that doesn't happen to come with a rootball. Plus water to ensure the root zone stays wet. This is especially important for trees collected in the summer.

Zach

 

[Waltron]

yea.. wishin I would have done that too. soil is pretty course. the bigger one I put a big layer of finer soil on top, ill moss it. I think they will both live. time will tell. I like the second one, personally. huge trunk chopped ones im always too worried about killing a nice breeder in the middle of the woods, although i know of a few dandy's out there that are tempting... no low branches on these ones just make me hesitant. I have another that was collected on a warm day in january, snowed the next day.. almost no root pruning straight to garden bed with a 1x12 under the roots, it has green buds for over a week now. none in the woods have that.

 

[Waltron]

RockM, Zach, whats your horn beam soil mix if i may ask? you seemed to mention mine was too coarse.. its sifted napa 8822, sifted calcine clay oil dry (I've had good luck with it in a mix) 1/4" lava, 1/4" pumice, 1/4" bark, 1/4" "bonsai block" handful of hort charcoal. probably way too expensive for what im doing with it, I do have one more hornbeam I will collect that Zach has given the green light as far as potential goes, ill cut the roots back more aggressively on that one and get it in a smaller container, and bury it deeper. I'm going to use these ones for my research this year, and leave some really good ones for next year once I have my data.

 

[base797]

Looks like the trees are just starting to swell, so no need to shuffle these in and out of the garage due to weather UNTIL the buds actually start to open. You can save some effort and just leave them in the garage till you start seeing some green.

Patrik

 

[Waltron]

Looks like the trees are just starting to swell, so no need to shuffle these in and out of the garage due to weather UNTIL the buds actually start to open. You can save some effort and just leave them in the garage till you start seeing some green.
Patrik

thats one way to look at it, and I've been contemplating that thought all week, its been so humid and rainy and warm, which is why I decided to collect when I did, these will go in the garage tonight and go back out on tuesday, i reckon. hopefully for the rest of the season. tomorrow is the first day of spring guys.