Saving 3 Horstmann Blue Atlas Cedar - can they be turned into bonsai?

[BPlantsnbonsai]

Late 2023 I had some landscaping done including 3 Horstmann Blue Atlas Cedar planted in one corner of the yard. Something has come up and the trees can't stay. I have looked into transplanting them and I was told it will likely cost much more than the value of the trees, and would only be 50/50 chance of survival. I also don't have a good place to transplant them to, so it isn't a great option.

I am curious if there is any way to bonsai them? They are about 6ft tall, 6-8 in trunk at base. I know conceptually that some trees can be cut back to the bottom few branches, but will these cedars tolerate that? Is it the wrong time of year? If they aren't likely to survive being dug up for transplanting, what are the chances they would survive being dug up and put into a pot?

Since they have to go anyway, I would like to try to bonsai them. I would appreciate any thoughts or suggestions to make the effort as successful as possible. I have kept tropical bonsai species for decades, and now that I have a house and yard I've started some maple bonsai as well. This will be my first time with cedar/conifer bonsai. I am located in northern Utah and temps are just getting into the 50s consistently for what its worth.

 

[James W.]

Certainly worth a try. A lot of work to dig a tree that size. Ask what the landscape crew would charge to just spade them up and drop them on the ground? Make sure you have boxes built before you start and a LOT of your preferred mix.
Those are big trees, are you prepared to handle trees that size if you succeed? Large trees are very awkward as well as heavy. I have a couple approaching and over 100lb and can tell you that you will need help or equipment to keep from damaging them when doing anything with them.
Opinions vary on the ideal timing for repotting Atlas cedars, from during full dormancy to after new needles have fully extended. I have had good success (twice) with doing a 1st potting from nursery stock after new needles are fully extended.
For what it's worth, I would do it and learn something regardless of the results.

 

[WNC Bonsai]

I know one person who has a Horstmann and I am on the lookout for one myself

 

[caffeinated]

Cedars generally hate having their roots messed with so the challenge will be getting a huge tree's roots into something manageable for potting the tree up. Have a couple really large nursery cans or wooden boxes prepared when you dig them up. I have a significantly smaller (1.5 inch trunk) Horstmann blue atlas cedar in a shallow, training flat, but I was able to do a top down repot on it while it was in a nursery can over a couple years, so that made the transfer fairly simple. You could do that for the second repotting, but first you'll need to collect as much undisturbed roots as you can.

 

[radhatter]

Where abouts are you located? I transplanted a blue atlas cedar with a 3.5” trunk and few roots successfully around this time a year ago in the Pacific Northwest. It’s happily putting on new growth now. I’d recommend a wooden grow box and a lot of pumice and Akadama or whatever your preferred medium is.

 

[WNC Bonsai]

Do they have to be dug this spring or can you wait a few months. The reason I ask is you could cut a ring around the roots using a spade which will force the tree to grow many more roots closer in to the trunk. Then in the fall proceed with the big dig. This should increase your chance of success.

 

[radhatter]

what I’ve read is the window to dig them is when they’re extending theyre first buds in the spring. Does that mean it’s the only time? Probably not, but it’s the most successful time as far as I have read, that correlates to the work I’ve done on my own successfully but I haven’t done a ton of experimentation beyond that.

For what it’s worth, a lot of yamadori digs are done in the fall and it’s traditionally a time of root growth, but you shouldn’t do any major reductions of blue atlas cedar in the fall

 

[WNC Bonsai]

what I’ve read is the window to dig them is when they’re extending theyre first buds in the spring. Does that mean it’s the only time? Probably not, but it’s the most successful time as far as I have read, that correlates to the work I’ve done on my own successfully but I haven’t done a ton of experimentation beyond that.

For what it’s worth, a lot of yamadori digs are done in the fall and it’s traditionally a time of root growth, but you shouldn’t do any major reductions of blue atlas cedar in the fall

My guess is it will depend on how much disturbance you do. If you dig a BIG rootball then you’ll likely have better success than with a smaller one. When I got my BAC in October 2 years ago I did a slip pot and only knocked off some loose nursery soil on the bottom of the rootball. It sulked most of last summer in response but is busting out all over this spring. Do you have a greenhouse in which you can provide good aftercare? Even a cold greenhouse would keep the humidity up and a small space heater could keep it above freezing, although that may not be much of a problem in Seattle. Good luck.