Juniper Yamadori Questions

Hey guys, first post here. This is kind of a row part question. First of all, I have 7-8 juniper I started preparing for a yamadori project this month, about 5-6 months ago. I dug around them hopefully forcing new, closer root growth, and I fertilized a couple times to gain strength.

I am in Southwest Florida and we have had a warmer winter than normal. We have had some cold days and nights, but then it just goes right back into the 70s and 80s. I have been looking forward to starting to work on these trees for a while now. I know that the shorter photo period has a lot to do with their dormancy as well, but the weather doesn’t seem quite right yet.

Should I wait until it gets colder, if it does, and if it doesn’t, then what?

Also, I watched the ‘yamadori aftercare’ video with Randy Knight, and he speaks highly of using coarse sawdust for his fresh yamadori. I was able to get my hands on a big bag of the stuff from a local lumber yard. I am wondering if I should use this sawdust as a sole growing medium for the first season or two, and if so, should I be concerned about pressure treating chemicals and/or natural oils from different types of woods such as rosewood?

I have read that the small amounts of copper based chemicals used these days in treated lumber is very safe, even for vegetable gardens designed for human consumption. I also would imagine that 99% of grow boxes being made by bonsai enthusiast are made from pressure treated wood as well, and never given a second thought. However, that is not using it as a substrate.

I am anxious to hear what you all have to say regarding both the proper timing and and the use of sawdust.

Thanks so much for reading and responding!!

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FWIW most people I know use cedar and not pressure treated wood for their grow boxes.

I wouldn’t use coarse sawdust for the entirety of the medium. I think it would hold onto too much moisture and not enough oxygen. Sawdust on the bottom and pumice for the rest of the mix is still the way to go.


I believe you’ve misunderstood the sawdust use. Sawdust is only used if you are healing the tree in on the ground with no pot. Sawdust should never be used in a pot or grow box. Assuming you get some roots when you dig, the normal procedure is to pot the tree in a box or other container using straight pumice to fill in around the collected rootball. The box or other container should be the smallest container that the tree will fit into, and the tree should be firmly tied in to the container so it won’t move. Once this is done you should leave it in the grow box, normally for two years to let it recover before doing any thing else to it. Once it starts showing some new growth after collection you can start lightly fertilizing the tree.


Thanks for the response Roger. Yeah I got that out of it, but have been considering trying this method on the ground over the weed mat. Never saw it done before. I guess I should have clarified that that was the intention. I also do wonder however, if doing so in a grow box would work as well if it has such great results? What do you think about the pressure treated aspect and or timing?

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I use pressure treated wood because that’s what I have available to me for free. I live in a newer neighborhood where several houses are under construction. I scavenge wood from the construction dumpster. I haven’t had a tree in there long enough to say if it’s good or bad, but so far everything has grown. I scored some old decking once, but I just burned through that. I should have got more of it.

For me I find that deck boards are the best. Perfect height and thickness. 2x4 and 2x6 are a tad bulky. I’ve also started burning all of the treated wood as a way to kinda seal it. I doubt it’ll prevent much leaching, but it does look better.

Here are some boxes I built recently. Bottom two are made of the last of the old deck boards. Top one was made using new deck boards and then burnt aka yakisugi. I decided not to scrape the burnt wood this time to see how it weathers over the months/years.

Here’s a box I made out of cedar and then burnt. With this box I decided to scrape it because I wanted to see how it looked compared to pine. Looks about the same tbh. Cedar is a tad more expensive and not as thick. We’ll see how that plays out.

This is a pine table top that I bought from Lowe’s. Burnt, scraped, and then coated with like 5-6 coats of tung oil. It’s beautiful. All of my boxes could look this way, but not worth it for a box. I do this same process with my stands though using pine.


Wow table looks AWESOME. Thanks for sharing and good luck to you with your endeavors in bonsai!


The sawdust use is only for healing in on the ground, sawdust should never be used in a pot. Regarding treated lumber, I wouldn’t worry about using it for a grow box, but if you are looking at sawdust from treated wood I think I would avoid that just to be safe. The sawdust healing in method is mainly for collected trees with a compromised or really minimal rootball. If you dig the tree and it has a reasonable amount of roots I would go ahead and pot it with pumice. Regarding timing of collection, just before or just as new growth starts in spring would be ideal. I don’t know when that would be in your situation as it is so warm there, but maybe there are some people local to your area that could provide advice on that.

Ok sounds more sensible. Most of what I read is just that, dig em just before new growth. However, most people that I’ve spoken to here and in my club, suggest doing it in the middle of the coldest weather we get. Doesn’t make a ton of sense to me, but I guess they know more than I do! Thanks again for your response!

Given that you live in such a warm climate it would make sense to dig the junipers during your coldest weather. They probably never really go dormant in your climate, so during the coldest weather you get they will be transpiring the least, thereby putting the lowest demand on the compromised root system for water after you dig them.

Now THAT makes sense. However, on the opposite end of the spectrum, why would you want to dig them in the spring when the demands are so much higher on the roots in other areas? If I can work this out in my brain, it may be a great AHA moment!

In the spring the stored energy of the plant is at it’s peak. As the plant breaks dormancy it will use that energy to grow new roots and new foliage, however the plant will only extend as much new foliage as can be served by the root system, so in the case of a collected plant it will devote much of it’s stored energy to rebuilding the root system instead of pushing new foliar growth. Since you don’t have much of a dormant period, if any, in your climate it makes sense to collect when the demands on the root system are at a minimum.


I agree with Roger. As Junipers get their energy from the foliage it makes sense to lift it when the foliage is less likely to be stressed with heat.


Listen to Rodger. He is on point and I am in agreement on all posts he has made. I will offer this. While Texas is not Florida the lows in winter are also not normally sub freezing for days and weeks on end. This week in Dallas we have been mid 60s and will touch freezing in the same week. Try and collect your Junipers in Jan/Feb, when they are most dormant and do so AFTER A RAIN if possible. This will greatly increase the collectability of the rootball and keep it, and the small roots you want intact. Keeping that rootball tightly bound and compressed and not letting it vibrate and bounce around and the mass to rattle loose between collection and potting is also paramount. As others have stated plant in a box, cedar preferably, in pumice. The Randy course sawdust healing in method is for his “trouble trees” and is outside the norm, even for him.

Good Luck!


I collected a Juniperus ashei (maybe virginiana) yesterday near Hico, into pumice today. Four hours to get the thing out of the ground. As I was working to get it out, I noted that some of the limbs / trunks that were laser straight were also very flexible even though they were a full inch in diameter. Have others noted this in the field? Trees that I’ve collected in the past have been rock hard and difficult to bend after they recovered even though the limbs were smaller.

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Not actually Spring but generally LATE Winter just before growth starts. That being said I’m usually late repotting because I have a lot of rain in these time frames and have to repot outside. So it’s weather dependent. However collecting is another story altogether.

OK guys lets get our plant terms correct here. There is a vast difference between HEELING in a tree and HEALING a wound. At least 2 folks got it wrong :rofl:.


Do explain please?? I didnt realize there was such a difference, but did find the use of the word a little strange in the usual sense…

Perhaps is etymology of word heel(of foot or hand)as in using heel to firm substrate around plant.
From middle english helere or old english haelan how healing was derived but is generally connected to medical practice or first aid as in the phrase a Doctor is a healer?
Not an english teacher personally but learned to be excellent speller after being a very poor reader and almost failing 6th grade. Have learned much in my many years. Cannot diagram a sentence to save my life but can recognize improper use of a word pretty good. :wink: And of course offense was not intended.

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So you’re saying what is being referred to as “heeling in” is simply compressing soil around the base of a tree with your heel? Interesting, had no idea. Thanks. Learn something new every day!!


Thanks for pointing out my error @WLKeugene. I was unaware of the term and had only heard it used by Randy in his stream. I applied it in my mind, and in his context as the “ICU” for trees with little roots, or a need to quickly and drastically increase root growth to increase health, thus “healing” seemed correct. Having now read a little about HEELING as a nursery practice after you pointing out my ignorance it makes even more sense. Randy having come from the nursery trade, of course used the term as it known in the industry, and then applied it to collected material. Thanks. More learn. More better. :crazy_face: