Mountain Hemlock (Tsuga mertensiana) Forest/Clump

[hinmo24t]

Just to clarify a few points, the mix you suggest is fine for root recovery above ground with excellent drainage. Not advisable for bonsai pot without modification. Also when trees are recovered in sea soil and pumice they have not necessarily been repotted in the sense that the native soil has been removed. Collectors rarely bare root collected trees. Often they are just surrounded by the sea soil and pumice and mounded as described by others. It is always important to note the changes required when adapting collected trees over time for life in a bonsai pot.
1. native soil should over time be removed using timing and techniques that suit the species.
2. soil mixes used in bonsai require sufficient stability for roots and anchorage. ie: addition of some heavier inorganic to balance such as lava or granite. Just pumice and sea soil will be too light and likely too high in organic for a bonsai pot. This will affect drainage and stability very quickly.
3. Find out from the collector or nursery what the particular situation with respect to native soil is and carefully examine the root ball before deciding on the mix to be used next or the amount of repotting to be done in the first session or two.
4. Mt. Hemlock vary in recovery time, as collected trees the root condition is unique to that tree. Be prepared to take time.
5. Foliage does vary with collection site variables and genetic differences.
6. Foliage does vary from climatic and genetic variation throughout the natural ranges. For experienced collectors they can often identify the nature of the collection site from the appearance of the foliage and tree form.

follow up question: for some small, and a medium eastern hemlock collected in spring/summer 2021, kept in native soil and uppotted, grew well until now, would you advise letting them run a few more years undisturbed or repot with some minor rootwork in spring 2022?
thanks

 

[JEads]

I would let collected trees recover for a year or two, at least before any work is done. when you see nice strong new growth, you can proceed carefully with root work, or top work. When doing root work, I would not mess with more than half of the root ball at a time, with a few years of recovery in between the halves

 

[hinmo24t]

I would let collected trees recover for a year or two, at least before any work is done. when you see nice strong new growth, you can proceed carefully with root work, or top work. When doing root work, I would not mess with more than half of the root ball at a time, with a few years of recovery in between the halves

thanks. and damn, ugly nursery containers it is again for them next year

 

[River's Edge]

I would let collected trees recover for a year or two, at least before any work is done. when you see nice strong new growth, you can proceed carefully with root work, or top work. When doing root work, I would not mess with more than half of the root ball at a time, with a few years of recovery in between the halves

John the first picture was taken in a place familiar to you I am sure. I recall when Michael started working with Hemlock after returning from Japan and moving to the Portland area, we typically left the top roots alone in the beginning and worked the lower portion first. The advice at that time was approximately 1/3 of the root ball at a time with recovery between sessions. Since that time I have kept to that approach with success!
This is with respect to an already acclimated tree after collection but no native soil removed, just supplemented with some pumice and sea soil around the original rootball.
This approach was based on Hemlock being very reliant on surface feeder roots, thus allowing the weaker areas to be strengthened before reducing the strong areas for sizing in pots or adjustment for planting angles. We used this approach when dealing with my first twin trunk Hemlock straight from the nursery pot when purchased from Anton. The overall process for root work was staged for smaller amounts at key times beneficial for root recovery. Basically spring and fall. ( early enough in the fall to allow root repair before hard freeze)
Some advantages to working the lower portion first with Hemlock is the ability to rejuvenate the core under the trunk early on, thus providing a strong central area as the overall root ball is reduced over time for Bonsai purposes in refinement. The other advantage is faster removal of thick anchor roots to enable planting in shallower containers as development progresses. The advantage to working 1/3 of the root ball at a time is the faster recovery and ability to reduce the timing between repotting. ( provided the tree does well)
Once the lower portions were strengthened it was easy to work down in stages to remove top roots and reveal the full base for better design and planting angle choices. I typically allow a minimum of three to five years for recovery after collection and basic root work to remove native soil along with developing a strong basic root foundation for Bonsai. One extra step I have discovered with adaptation of collected Hemlock is to plant them a bit deeper in the grow box or Anderson flat when first collected. The extra soil on the surface roots is easy to remove later but encourages better surface root survival and acclimatization for the tree during recovery.
Here is my example, twin trunk in nursery pot for preliminary pruning and rough design with Michael and Bobby November 2014. ( first picture) After that one session with Michael and Bobby in Milwaukee, I began the root work to remove native soil and develop a proper root base beginning in march 2015 at home. Rivers Edge Bonsai.

Stage one March 2015 ( bottom layer and central core) place in Anderson flat
Stage two Sept 2015 ( 1/3 rootball) divided in segments like pie, three weakest sections done first.
Stage three March 2016 ( 1/3 rootball) three additional segments.
Stage four September 2016 ( final 1/3 ) last three segments ( placed in maintenance pot)
Stage five March to Sept 2017 reduced from top layer to expose more of the base and nebari.
March 2018 transferred to show pot with minor repot

Approximately 2 1/2 years for root work and transition from nursery pot to maintenance pot to Bonsai Pot. During this time the weakest areas were dealt with first to allow the strong areas to keep the tree as healthy as possible for faster recovery to the next stage. Each session involved removal of native soil, dead roots, cut back overly strong roots and carefully replace native soil with bonsai mix.
The first three pictures below track the progress from nursery pot to show pot. The last picture shows the current progress towards refinement.
Note: using this slower repotting process allowed me to prune, wire, bend and develop the tree during the same time frame.
Over that time frame I received valued long distance advice from my sensei Boon, early assistance from visiting artists Matt Reel ( Reelbonsai ) , Bobby Curttright ( Cascadia Bonsai) and Bob King ( particularly with wiring and design tips) and lots of additional suggestions from my fellow members in the notorious Tailgate Bonsai Study group. The Tree has been completely wired, unwired and redone six times since 2014. Fortunately each time I do it now the amount required gets less and less.

 

[ghues]

@NHATIVE -
Can’t add much to Frank’s post.
Post Yamadori treatment techniques do vary but the slow transition to a pot can’t be emphasized enough.
The one that has worked- After collection I put them into a raised garden bed (early morning and late afternoon sun). The soil in the bed is a real mixture of well decomposed compost, sand, bonsai soil scapes (pumice, granite, perlite, lava) and a product similar Seasoil. Laying out the rootball and then covering it with 2” of mostly Seasoil. Many Hm, Yamadori can have a thick duff/humus layer. Sometimes many companion plants/mosses are also embedded in this layer. I leave them undisturbed for two growing seasons. What I have found happens is that much of the Seasoil and the original humus/duff layer has decomposed, companion plants may have emerged and it’s much easier to explore it, to evaluate and determine its next steps.
The attached photos are from one I collected at 4509’, late summer 2019. Didn’t do much of anything in 2020, (thought it was dying at one point), it has done much better this year but buds are still small.
Bring on more Mountain Hemi’s.