New nursery stock Satsuki Azalea Osakazuki development advice

[Bubsamecium]

Hi everyone, I picked up these two Osakazuki satsukis in 3 gallon pots the other week, here's a close up of the trunk and an overhead view. I am very much a beginner when it comes to satsuki azaleas, but I have been using Rick Garcia's book, @Deep Sea Diver 's Evergreen Azalea Basics, including Satsuki doc, Joe Harris's lecture on Bonsai Mirai, Satsuki Channel on Youtube and other youtube videos, among a lot of very helpful posts here on BNut and around the internet for guidance.

I'd like to grow these two significantly larger while starting to set some structure for a few years before moving into training pots and starting to style and refine.
I'm in the middle of a front yard project and would be able to set aside some space to field grow- in which case what soil mix should I use? I can get a bulk rhododendron mix (bark (primarily fir and hemlock I believe) mulch and soil) readily, but not sure if it would need better drainage or other components.
Alternatively, I can repot and pot up; I do have a bag of kanuma (but it is quite expensive) and easy access to pumice, but I know it might be more economical to save that for a later refining stage. I could also pick up some peat and pumice and bark mulch as a developmental soil mix instead.
For repotting, I understand bare rooting and root washing is optimal; I could use some advice for how to root wash.

I was quite amazed by the trees shown here

(thanks @Glaucus for the suggestion!), but I'm not sure how to apply that technique to a small nursery tree; what I took away from it was: only prune once a year- in the late winter (but prune small buds on the inside or buds coming off the roots any time). Keep only 2-3 strong buds on each branch, let them lengthen. But in the same video I see him leaving no buds on some branches, and I'm not sure if he's pruning to last year's growth or beyond (going against some tips I've heard on BNut and Joe Harris to always leave a small amount of this year's growth when pruning back).
I'm also not sure how to achieve that spectacular trunk and branch thickening, especially seeing @Glaucus's experience with the Violetta.

Both of these nursery trees are quite shrubby with large branches emerging from/below the soil line. When would you prune back some branches as part of this primary development (selecting primary branches)? If the larger branches need pruning, do they need special attention- eg. pruning halfway through or leaving a few cm (inch) stub and then pruning it back convex close to flush the following year to avoid root die back?
Speaking of selecting primary branches, should I wire now for some general curves and shape, noting that I don't know what design direction to take these plants in just yet?

Another concern is some yellowing at the tips, which has happened since I got the plants. My best guesses are that it might be related to overwatering (they got a ton of rain overnight one night in particular), or could it be normal seasonal change? I'm also a bit concerned I've seen some white flies in the back yard where they are now... Does this necessitate an emergency repot? I suspect the first frost where I am (coastal 9a PNW) won't arrive for another month, and I do have a garage-ish area to shelter if need be.

Thanks in advance everyone for your thoughts and suggestions!

 

[Deep Sea Diver]

Good Morning!

Whew! That is a whole lot of questions packed into one post.

Basically asking for the entire book on satsuki, one in which no one has ever attempted at this point.

The resources mentioned are good, yet do not cover ground growing

So let’s break this answer down into just the ground growing element to start with.

First of all. what are these presently potted in? If standard pert perlite mix we use a combination of peat, small bark and manure when ground growing. Roughly 30:60:10. Or just small bark and manure when no peat is available 90:10

Don’t know what is in rhododendron mix, but guess it would be fine to use but would assure it has small bark in a percentage of about 40-50% to sustain the grow.

Plan at least 3-4 years in ground and protect from rabbits, dogs etc - especially during the winter.

If one plans to set aside an area to field grow, please ensure morning sun afternoon part shade.

Be sure the growing area has sharp drainage. Or areas have multiple layers of clay that create poor drainage In this case wh we use a build up atop the clay layer with media mix described above. Guessing you know how to do this living in our area.

Pruning is fine ahead of planting. Might seal all cuts. Seal - then putty big cuts. This prevent dissication. While this doesn’t have to be done, we find a tad quicker recovery and less chance of rotting in the long run.

Once the azaleas are back in pots we are very much more cautious for pruning large branches, using a 2-3 step method as Joe H partially described. This is due to the azaleas not being as resilient in a pot and it’s propensity to die back all the way to the roots from the cut area… sometimes creating a hollow trunk.

Not sure about the tip yellowing. Doesn’t seem pervasive at this point. There is winter due back of the spring leaves beginning though. Pull the Osakasuki out of the pots and inspect the bottoms. If wet, scrape off the lower area and put in small bark. This ought to help the azalea. Hopefully both will be planted in ground next spring?

Cheers
DSD send

 

[Glaucus]

I got some larger satsuki plants from Italy two years ago. And I planted them in my garden in autumn and 3 of them died. So while I am supposed to be an expert, and azaleas very rarely die on me now, and considering I did zero pruning, I always question my own expertize. Because I am not quite sure why they died.

First off, the yellowing. No, that is not autumn colour. It is either a deficiency of an immobile nutrient. Or it is a pest. The older leaves seem quite dark so it is a new thing.
There is this theoretical nutrient deficiency assessment flow chart, but in practice it is not usually very helpful:

Nutrient Deficiencies - MSU Extension Soil Fertility | Montana State University

landresources.montana.edu

I have seen this growth as well, when later in summer the new tips start to look weaker/more juvenile, and yellowish-orange. Yes, I suspect it is wetness more than a specific nutrient being deficient in the soil.

So one of the first thing I would figure out if these potted azaleas can stay under the rain for all winter. Are they at the nursery? Or are they in a sheltered area where they get way less rain?

Then, for field growing them, it is important to prepare a bed with good soil. Rhododendron planting soil is very good. But your local version of that is mostly pine? And not peat? Besides that, adding a substrate to the soil, like lava, very coarse sand, kanuma, pumice, grit, can be helpful. Clay soils are very bad. Old garden soils that form chunks that stay together when wet are bad. The first goal would be for the roots to grow out of the potting mix into your field growing soil.
Bare rooting an azalea that is in soil or peat is hard to do. DSD has some guides on it. You need to water jet out the soil. But you do need to do something to set up nebari. Because if you completely ignore nebari, what is the point of investing in field growing for bonsai for years. You are paying years of growing time to thicken up a trunk that has poor nebari.
You'll have to decide how close to bare rooting you want to get. If you want to go total bare rooting, or near bare rooting, I would sow off about the bottom 2/3rd of the root ball first. And you'd also prune back a lot on top.
You will have to do this late winter after the roots start growing but before the leaves start growing.

The main goal for pruning would be to prevent reverse taper. The second goal would be to select a trunk line with the most natural movement. And decide on if you want one trunk or multiple. Likely, you will get a trunk that has very little movement, but eventually will get age and taper. From the first picture, it seems there is some potential here. The points in the trunk where you get side shoots, those you may be able to use to get movement, by stringing together several straight sections that are at different angles. It would mean pruning out large sections of the plants, back into old wood. Generally, the advice is to as much as possible, first prune a main branch back to just a few leaves, so those leaves keep all the roots connected to that branch alive. And then to later on, like 1 to 3 years later, remove the branch entirely. Because roots are directly connected to a branch, if you prune the branch, those roots can die. And then a whole section of the trunk can die. Which can cause a hollow trunk. Probably not a risk at this age for a nursery plant, but this is why removing a large branch in stages is recommended for an azalea bonsai.
But also with this nursery material, that would likely take too much time.

And because you want to do a harsh operation on both roots and the top of the plant, and because the timing is late winter, I wouldn't be entirely opposed to doing this operation, and putting it back in a pot for at least a year. So you can protect it from late frosts. Probably, you have less of those in your climate. But if you have an early start of spring, then still late spring frosts when the azaleas are pushing new growth, this is kind of throwing a spanner in the works.
But if you do want to grow these plants for at least 5 years, then putting them in the full ground makes sense. And you would probably only dig them up once they are ready to go into a pot. So again this makes setting up the roots/nebari first so important.
And then maybe moving them from a pot to the full ground about 14 months later, the spring after but only when frost risk is gone.

I actually have a bunch of nursery Kozan for which I hope to do the same thing. I put two large Chinzan in the ground and only wired up the nursery Kozan. I was too lazy to take pictures, though. I have these, and cuttings with trunk movement, that I need to set up the roots for as best as I can. All next spring. And then maybe spring 2026, put them in the full ground.

And then you just have to deal with your growing season being less than what they have in that Japanese video. Lattitude-wise, Kanuma in Japan is the same as Monterey, California, which is just below Santa Cruz. That, plus they use a poly tunnel to extend the growing season about 1.5 to 2 more months. You cannot compete with that on Victoria without a poly tunnel.

 

[Bubsamecium]

Thanks to you both! Sorry for the extensive questions, I know the experienced guys on the forum get asked a lot of the same very general beginner questions, so I'm hoping to hone in with some more details for your advice. Also trying to plan a few steps in advance!

These tips are extremely helpful! It sounds like my first priority is checking the roots and repotting/planting. Especially with the yellowing tips, it sounds like maybe the timing would be to check and wash the roots without bare rooting for now to be delicate (now?) and repot into the same 3 gallon pots for now while doing some (hopefully not too much) root work and setting nebari, perform some fall mesuki pruning (trunk shoots, downward growing shoots, weak shoots, and removing leaves), and then plant in the ground in spring (and getting closer to bare rooting then)- or maybe wait a year before putting them in the ground?

I presume they're in a standard nursery mix, maybe peat and perlite. @Deep Sea Diver Yep, I can make a mix with peat moss and bark/compost to pot it back into. Would you add some pumice to this mix in the pot?

I can put them in a sheltered area away from rain, but much less sun.

For the ground, @Glaucus the bulk "rhodo mix" I can get is a bark (fir and hemlock (not pine)) mulch and soil mix without peat; not sure about specific ratios or what constitutes the soil. I could amend it with some pumice to help with drainage, as well as some long osmocote plus for fertilizer.
I could also put them in the ground in like 15 gallon grow bags and really tailor the media in the grow bag similar to the mix DSD recommended. (My thought for possibly using oversized grow bags in this case would be for having a more optimal soil mix in the bag while taking advantage of ground conditions, not for air pruning etc).

Yep, I'll be protecting from the local pests with fencing- which are deer that roam the city!

Once they've hopefully recovered later in spring (like mid April?), maybe that would be the best time to prune some larger branches to prevent reverse taper? Will definitely be sealing, I have some Kiyonal but hard to get my hands on Top Jin M, I hope that will work.

Thanks again for the advice everyone, much appreciated!

 

[Deep Sea Diver]

Thanks to you both! Sorry for the extensive questions, I know the experienced guys on the forum get asked a lot of the same very general beginner questions, so I'm hoping to hone in with some more details for your advice. Also trying to plan a few steps in advance!

These tips are extremely helpful! It sounds like my first priority is checking the roots and repotting/planting. Especially with the yellowing tips, it sounds like maybe the timing would be to check and wash the roots without bare rooting for now to be delicate (now?) and repot into the same 3 gallon pots for now while doing some (hopefully not too much) root work and setting nebari, perform some fall mesuki pruning (trunk shoots, downward growing shoots, weak shoots, and removing leaves), and then plant in the ground in spring (and getting closer to bare rooting then)- or maybe wait a year before putting them in the ground?

One of the best techniques we use to grow out azaleas is to put them right in the ground in an appropriate location. See my previous post. Presently we have over a dozen growing out successfully. Another dozen have been harvested in the past year to prep for bonsai containers. Did try to plant some borderline areas with indifferent health results. None died, all were relocated and have done fine. Rabbits is our major hazard during the winter.

Prep the spot. If well draining soil is present No root washing is needed. It’s not a very good time of the year to root washing, particularly as we are both going smack into the rainy season. Chop the bottom 1/3 roots straight off, then use a chop stick to loosen roots a bit. Nothing major. No tearing or ripping the roots.

Optional. Use a saw to cleanly cut the bottom of the root ball into quarters towards the top of the rot ball. No more. Gently prise the quarters outward a bit to spread the roots. This will get the nebari headed in the right directions.

Azaleas develop nebari very quickly with proper technique. To get a jump start (in the case where there is no clay lens - really hard to dig through) close to the surface in the selected planting area, get some old/new 3/16-1/4” plywood to place flat under the roots prior to burying the azaleas…. Do not use tile, metal etc as recommended for other trees.

If you see (not think - the roots will be mushy) there is root rot present. Lopping the bottom 1/3 off ought to solve most issues. Would advise spraying 3% H2O2 on the roots just prior to planting/potting.

Once completed, bark over the planting area about 3-5 cm thick in a doughnut around the edges of the roots. Then fill over the roots with 2 cm. Leave in the ground 3-5 years.

Wait to prune, except minor cleaning, out until next year after bud break.

If you intend to put these azaleas right back into a container… Do not use use the same containers if you see root rot. Get similar or slightly larger nursery containers and repot in these. Toss the old containers away. Follow the same steps as above to prep the root ball and back fill with a small bark peat and perlite mix. Prune next spring.

My opinion is planting in these ground works best in these cases… but your tree, your choice.

Cheers
DSD sends

I presume they're in a standard nursery mix, maybe peat and perlite. @Deep Sea Diver Yep, I can make a mix with peat moss and bark/compost to pot it back into. Would you add some pumice to this mix in the pot?

I can put them in a sheltered area away from rain, but much less sun.

For the ground, @Glaucus the bulk "rhodo mix" I can get is a bark (fir and hemlock (not pine)) mulch and soil mix without peat; not sure about specific ratios or what constitutes the soil. I could amend it with some pumice to help with drainage, as well as some long osmocote plus for fertilizer.
I could also put them in the ground in like 15 gallon grow bags and really tailor the media in the grow bag similar to the mix DSD recommended. (My thought for possibly using oversized grow bags in this case would be for having a more optimal soil mix in the bag while taking advantage of ground conditions, not for air pruning etc).

Yep, I'll be protecting from the local pests with fencing- which are deer that roam the city!

Once they've hopefully recovered later in spring (like mid April?), maybe that would be the best time to prune some larger branches to prevent reverse taper? Will definitely be sealing, I have some Kiyonal but hard to get my hands on Top Jin M, I hope that will work.

Thanks again for the advice everyone, much appreciated!

Would advise spraying 3% H2O2 on the roots just prior to planting/potting.

 

[Bubsamecium]

Thanks again DSD, I really appreciate it! All that advice, especially on root work technique- cutting, setting the nabari, and spraying the roots is incredibly helpful, as are your soil recommendations.
Checking the drainage of the bulk rhodo mix I was looking at, the drainage seems quite poor. Would you have any advice on improving drainage in the field? I could mix in coarse sand in any ratio, or even pumice in light amounts specifically in the area I'd be looking to plant in the ground.

I'd definitely like to put them directly into the ground as opposed to back into a container if you've had good success with that. Timing wise though, I realize I need to check the roots now to make sure there isn't root rot or other issues; but is now a good time (especially where we are in the PNW) to do that root work (without bare root and root washing) and plant directly into the ground?

 

[Deep Sea Diver]

••••
Thanks again DSD, I really appreciate it! All that advice, especially on root work technique- cutting, setting the nabari, and spraying the roots is incredibly helpful, as are your soil recommendations.

You are most welcome!

•••• Checking the drainage of the bulk rhodo mix I was looking at, the drainage seems quite poor. Would you have any advice on improving drainage in the field? I could mix in coarse sand in any ratio, or even pumice in light amounts specifically in the area I'd be looking to plant in the ground.

Adding small bark will help a lot. In fact when we get dig yamadori and replant for recovery the media we use its 100% smaller/medium bark.

••• I'd definitely like to put them directly into the ground as opposed to back into a container if you've had good success with that. Timing wise though, I realize I need to check the roots now to make sure there isn't root rot or other issues; but is now a good time (especially where we are in the PNW) to do that root work (without bare root and root washing) and plant directly into the ground?

The azaleas should be fine for planting more given the steps are followed and you use the protections/precautions mentioned.

Will likely be off line until early December. So good luck! Will check in later.

Cheers
DSD sends