Hard pruning of birches not a good idea. Nurseries produce clumps by planting several plants close together. These tend not to work out later when planted in the open as solitary landscape features as the trunks often lean away from each other over time. When included in a grove of others of the same kind the competition for light keeps them growing upward better.

As long as the storage area remains sufficiently cold and moist you should be able to store them inside over winter the same as commercial producers and sellers who dig them in fall and warehouse them over winter for early season sales.

i see two potential problems...

first.. a week of warmer weather in mid winter ... so the issue is ... how do you maintain dormancy in freak heat waves ... in pots.. in an enclosed garage

second ... the potting ... how do you keep the soil moist in the pots... without drowning or making an ice cube ... and what media will work best ...

frankly .. in my zone 5 ... i would 'heal them in' ... into the veggie garden... anywhere ... and just plant them properly at the right time in spring ...

mother earth has a way of staying real cold... during winter heat waves ... holding and tempering water ... etc ...

my unheated.. uninsulated attached garage... can get to 60 on a 20 degree sunny winter day .... yours may NOT be the refrigerator you think it is ...

ma earth .. even on a 60 degree air temp day ... will retain the cold in the soil.. below the first inch ...

let her do the job .. it will just be so much simpler ....

now.. plant these two about 2 or 3 feet apart.. and you will have your clump ...

old school pruning says reduce the canopy to aid root growth after transplant..

new school says.. more leaves.. more food production.. equals more root growth .. means faster re-establishment ...

so i would NOT severely prune after transplant ... since i have had a lot of luck with the new school ... though i have no problem pruning out crossing or broken branches ...

you go girl ... good luck

ken

PS: why did you dig them up now????

Yes, I have seen the three tree method that some growers use to produce multi trunk ornamental trees. I even planted a paperbark maple tree that had been handled like that. One of the paperbark trunks dominated and the other two died off each at different times. It did not seem to matter what I did to try and save those, they still died while the dominant one thrived as if no stressors of any kind existed for it.

Also planting three young trees together is the technique I myself had tried to get a multi trunked River Birch tree. Five years later, one of those trunks thrived and now has a 3 inch wide trunk with beautifull pealing bark, and which has grown to about 10 feet tall. The other two trunks are currently about 4 feet shorter, also with some bark pealing and with only about 1 inch in trunk diameter. This drastic imbalanced look is why I dug the two shorter trunks, and now have them in bare root form.

I have seen other reports of people having success at growing a new single main leader by the cutting back nearly to the ground of the damaged main leader. Of course those damaged trees are usually fairly well established.

So I do not know why I could not do the same thing with my single trunked birch trees. That is, as long as I do it at the right re-established root development point.

Is this truely a bad idea? I do think that my trees are nearly twice as mature than what past growers generally used for clumping out multi trunk birches, but if I do not begin the process to eventually prune out the current one inch wide trunks for these two trees; they too will likely dominate too much over any new sprouts which I might get to pop up out of each of their own root balls.

I have also seen what you suggested concerning the trunks of clumps spreading to far; that is on a neighbor's birch that has only two leader trunks, and which is almost 30 years old.

Is my only other option to keep them as single trunked trees. Is this delima, also why I have had such a difficult time finding young multi-trunked Heritage birch trees at my local nurseries.

Also am I wrong in thinking a three trunked rootball would tend to grow more slowly and end up with less height potential if all three trunks emerging from one rootball grew at a relatively well balanced rate, and no trunk is allowed to remain, which seemes to so drastically dominate over the other two.

I dug now because they had already gone dormant and I thought if I bare rooted them they would suffer less transplant shock when I try to let each of them develop a good mass of rootball again.

As for my desiring to pot them up already, would it be better to keep them out side? Of course potting them outside and in order to keep the roots from freezing I would have to go to all the work of sinking these two 15 gallons sized pots. Or expensive for me to get enough mulch needed for covering such large pots thick enough to protect the roots from freezing.

My garage is attached to the house and I think it is insulated. I also have a black-out curtain on the window, and this keeps it dark in there much of the time since we generally keep the door closed when not in use.

Our temps have been ranging from the high 20s at night and only a few days of the month when temps reach 58 degrees F. for only a few short afternoon hours of the day.

It is also late enough in the year that we are having more colder days and nights than relatively more mild ones.

That is why I thought they might do well if I potted them up and kept them in garage. The garage is located on the northwest corner of my house, and that is the direction which the cold northern winter winds come blowing through.

Does this still sound like my potting them and overwintering them in the garage is a bad idea?

Kat, the idea of cutting trees back to the ground in order to get multiple new sucker development works better in some species than others. Birches are not especially well suited to this treatment.

And my own opinion is that clumped specimens are not intrinsically more attractive than single stemmed. Out in the woods, you will occasionally see where two trees of different species both got their start at about the same time, and in very close proximity to each other. Alongside a road not far from my land, there is a hemlock and a N. white cedar growing right together. I like this very much, but consider it a bit silly to try to replicate this effect on purpose. And in my former, private nursery job, we potted up many a "clump birch" which, as Bboy stated, are simply three single stems jammed together into a single pot. There's nothing more "natural" about this treatment than going single stems.

Just my HO!

+oM

Alright, ken. I wish you would leave at least half of each sentence intact. You always have something good to contribute (unlike myself sometimes) but man... the breaks in your writing there is just painful! It does not flow, I have to work to read it. And I mean WORK to read it. At least make the breaks between the (...) less frequent. Please.

Ok,

To the OP, why did you feel as if you needed to remove these plants from the ground? They will resprout just fine in the ground, moving them around will only delay the end results and stress the plant.

+oM, you certainly would love to see the single trunked Heritage birch that I created after digging the two shorter ones. That tree has the most beautiful colors of trunk revealed as the bark flakes off, and its canopy for the first time has developed very nicely. The last two years were dry both in summer and winter. Add to that we had some early spring late freezes which zapped them after they had broken dormancy. Not to mention last winter when we had the worst icing that damaged many area trees. All that made these trees struggle. Thankfully Spring and Summer of 2008 received record rainfall amounts. Almost once and sometimes twice a week it would rain. So this made the trees I dug and the one I left growing looking very good with very nice shaped canopies. That is especially true for the larger single trunked birch I did not dig up. It certainly is amazing to see just how adaptable this tree has been.

I also purchased a 12 foot tall single trunked Heritage birch tree from a local nursery this summer. They had reduced the price due to its top looking stressed and it not having mor than a one sided canopy. I planted it in an area of my yard that receives lots rain runoff from my neighbor's yard, and there is not room in that area for a multi trunked birch.

So with these two single trunk birches, one on a property that I have recently put up for sale, and the other one in my back yard; I really would like to turn the two I dug into three trunked birches. One I can give to my friend who needs it to distract the view from an ugly utility box in her back yard, and the other for me to plant in the front yard of a smaller house that I might move into later in Summer or Fall of '09.

Since I already failed with trying to get a good three trunked tree by planting 3 of Heritage birches together. Now I am more willing to risk failure just to see if I can manage to get these two single trunks trees to throw up multiple trunks.

Of course I am certainly aware that effort will surely fail if I don't manage to handle them right though the winter. At least they are dormant now and need less attention; just as long as I do not do anything with them that will cause them to try and break dormancy too soon, dry out their roots too much, or allow the roots to get too wet and start to rot.

Alright Kat, I see the big picture now. In view of all you've stated, perhaps it would be worth a go to see what, if anything , you get in the way of sucker development on these two.

In the mean time, garage or outside, I have a hard time seeing where it makes a whole lot of difference. Let us know what happens.

+oM

Thanks Ken, +oM, and fledgeling for taking the time to read my long posts and for your responding with your opinions and reports of past experiences.

After considering all I read, it seems best for me to pot them up and keep them in the mostly dark garage. This should allow me to more easily keep the potting soil only barely moistened.

This might be a bad idea, but I also plan to shorten their canopies in half. Never would I do that if I planned on keeping the present main trunk, But I figure that with the remaining canopy the 2009 growing season will be enough for each tree to regain at least enough root structure to fill the 15 gallon pots, and then maybe near the end of the 2009 winter; I might get away with cutting mostly away the present main leader of these to trees. Hopefully then the soon following spring rains actually does encourage the root system to send up a bunch of suckers. I guess only time will tell if there will be enough new suckers for me to grow and see which three for each tree will be the best to keep.

If my efforts succeed, or fail; I'm sure it will remind me to post the results; just incase there is more advice others might give, which could enhance my efforts at that time.

Ended up changing my plans on how to pot-up the trees.

Went to local nursey, and got enough of the specialized potting soil that they mix-up, and I mixed that with that a large bag of their fine shedded, with a few larger pieces of pine bark mulch. I used the resulting mixture to plant these two dormant trees, because I did not want to use the box store potting soils. That is because all I saw those box store were selling was either Miracle Grow or Scotts potting soil that also listed containing fertilizer.

Not certain if this is right or not, but instead I thought it important that the potting soil I chose to use had no fertilizer in it while these, transplanted into pots, trees needed to stay dormant.

Once I unwrapped the trees' rootballs and removed any remaining sandy loam soil, it became clear to me that one of the trees' rootballs was large enough to transplant it into a 25 gallon sized black nursery pot. This tree had been taller than the other one before I cut it shorter, and there was one almost 3 foot tall thin, but nicely branched sucker growing up from the base of the trunk. Seeing how nicely developed the sucker appeared, motivated me to change my plans and cut back this tree's main leader trunk all the way down to slightly above the rootflare level.

The other tree had a rootball small enough to fit into the original planned 15 gallon size black nursery pot. It's trunk had no suckers growing up from it's base, so I only shortened it's main leader trunk enough to keep slightly less than half of it's original canopy.

I plan to give these pots only a gallon or so of water every month to 6 weeks, as long as I am keeping them in the dark garage over this winter. Plan to adjust that amount though if the potting soil gets too wet, or too dry.

Good thing, last spring, I had kept the 25 gallon sized pot, which my 5-6 foot balled and burlaped degroot's Spire had come in. Otherwise, in the beginning of winter, it might have been a lot of trouble trying to find a source from where I could purchase such a large black nursery pot.