Japanese Boxwood #18 - too tall: thread graft reduction

Boxwoods (Buxus microphylla) are one of those terrific slow growing shrubs that people think they can just plant out and forget about.  They always look glossy green, grow in nice small tufts and seem to take forever to change.  BUT if left alone, they will turn to very large shrubs and even small trees. 

A friend and fellow Austin Bonsai member had this line of shrubs beside his driveway which were not only taller than a person at this point, but were growing out into the pavement making it harder to park.  I'd say the shrubs were all more than 6 feet tall, and were probably at least the same width.  He generously opened his yard for several of us to collect.

2006 March.  The "before" shot.  Lots of green out on the tips, healthy shrubs.  Probably around 30 years old.

 

 

 

The soil was very thick and full of stones, hard to dig through.  We used rock bars, saws, flooding with water, and just about every other trick to get these out of the ground. 

It's out and now I can inspect the trunk better.  I like the silky twisting branches.  This particular one has almost a lack of bark.  Age and elements have worn it smooth.

Laying it out though, the full height of it is startling.  Some of the stretch-wrap tape that I used to tie the branches (or trunks) together can be seen.  There was no way to get in between these plants otherwise.

The heavy clay soil didn't need to go home with me, so it was washed off into the hole, cleaning the roots.

 

 

Roots are washed some, now the top needs reduction. When cutting back Boxwoods here in Central Texas (and I've heard it can be different in other parts of the country), you must leave green leaves out on the end of all the tips to ensure survival of the branch.  I've tested this theory, and ended up with both dead branches and dead trees when I've cut back past the foliage, leaving only stumps.  Unfortunately at this dig, the nearest green tips are still waaaaaaay out there!

Once back home, and propped up on a neutral background, the problem is even more stark.  The height has been reduced, but it's still almost 5 feet tall.

 

Roots are washed off now really well, getting all the old soil out, plus all the trapped stones.  This cuts the weight in half! 

The top of the nebari (root spread) was uncovered, and one last photo was taken before planting it.

Here it is in a pot (a large cat litter pan).  Ridiculously tall and prone to knocking over, this is one silly looking pre-bonsai.

2007 February.  I really should have taken another before shot, but after tiring of how it was difficult to move and always was growing into its neighbor's space, several branches were removed.  Others were gradually chased back as I found another green bud that opened for me.  By 2007, I decided I had to do something radical to get the size down to a better proportion.  The solution - I thread grafted branches in lower down the trunk.  In fact, I made 12 thread grafts on this Boxwood at this time.

Here is a close up of one area to see the brand new branches.  But wait - how do you get the branches with leaves through a hole in the trunk if you can't defoliate them?  Well I worked something out.

step 1: A bare trunk area that needs a future branch

step 2: find a shoot that when bent to the right area, will be long enough to go through the trunk.

step 3: strip off the leaves on the area that will be inside the trunk once it is threaded though.  Also cut off every other leaf on the ones that remain so they alternate.

step 4: wrap the shoot in non-sticky green plant tape starting at the base.  Use a bit of tape to secure the end so it doesn't unravel.

step 5: Wrap it tightly like a cocoon and put a tiny piece of tape on the end to keep this side from unraveling.  Along with the branch inside, it is helpful if you wrap a length of thin wire which will help in the next step.

step 6: Carefully drill hole through the trunk with a slow speed, being careful not to burn the edges of the cambium (living tissue), and paying attention to the angle that the branch will exit the trunk.  Feed the tape through the hole (pulling the wire that is inside the "cocoon" makes this so much easier) and pull the branch through.

step 7: Unwrap the boxwood burrito you had made and unfurl the leaves.  There may be creases in the leaves, but as long as they aren't broken off, they'll continue to function and feed the branch.

step 8: seal both the entry and exit wounds with putty or another kind of wound sealer.  I also put a piece of a chopstick in the hole to help take up some of the space and to push the new branch to the top of the hole where it should graft quicker.  Now, just leave it alone to grow and put on tissue to fuse.

2008 February.  All shoots were allowed to grow last year unhindered.  Some of the grafts have taken, so a few of the high branches can be reduced now.

Ah, that's better!  Now it's much easier to carry around!  More reductions for the future, but that's it for today.  Leave these alone now to grow, grow, grow.

2009 January.  All the new branches have filled in and more grafts are beginning to take.

Here is an example.  The "entrance" side of the thread graft is beginning to die back while the "exit" side is bulging and grafting to the trunk. 

Another shot.. even if it looks like it must have taken, leave the back of the thread graft shoot until it dies back naturally.  If it is cut too early before it has truly bonded, years of growth are lost and the whole process has to be repeated.

While those are working, I put in more thread grafts.  Constant improvement should be a goal with Bonsai.

2009 January. After evaluating the health of the grafts, I took off the remaining height.  Finally it is down to Bonsai proportions!

2009 September.  All shoots were allowed to grow to strengthen.

Then the whole bunch are cut back and wired (most for the first time) to give movement.  The stub cuts are carved to give taper to the ends.

2010 March. The silhouette is beginning to fill out now.  The soil at this time is 4 years old and breaking down.  It is in bad need of repotting.

Out of the pot, the roots look healthy.

They are washed, removing all the fines that have built up.  There is even some original soil found in the center that is also cleaned away.

And it is put into its first Bonsai pot, a large mica pot with fresh open soil to encourage root health.  This photo was taken at night, giving me funny colors!

 

 

2011 March.  The foliage has thickened and grown well.  Up until this point, I've been working towards building up the foliage mass.  Now it's time to reduce it.  If I don't selectively reduce the branches and leaves, the inner shoots will begin to die and I'll be left with a shell of green with only bare wood inside, much like it was when it was collected.   

Thinned and wired out.  John Naka, considered to be the father of American Bonsai, was known to say "design your trees to allow space for the birds to fly through".  You need the open space to define the shape as much as the clouds of branches.

2011 December.  Long branches are being controlled to create fine branching.  Winter is a good time to evaluate our trees, even evergreens like Boxwoods.

The shape is going in the right direction, but there is an unsightly area where the large branches were reduced and tapered to the new lead branch.  Boxwood aren't known for healing over large wounds, though some of these have begun to callous pretty well:

A solution may be in a tape-wrap technique.  To speed healing, the same non-sticky green tape can be tightly wrapped around a wound.  Where the callous tissue wants to bulge and bubble up, the pressure from the tape encourages it to make a thin layer towards the center and knit together.  I have done this successfully with Maples and other plants, and thought.. why not try it with a Boxwood?  So the ends were wrapped up.

2004 March.  Foliage filling in.

And then thinned.  This time when looking at it, I thought - why not use sacrifice branches to speed the healing of the wounds too?  This is where a branch is selected to run wild to feed the area directly behind it.  After a while it is cut off (thus the term "sacrifice").  This is a technique to enlarge a branch, but also to heal wounds faster.  I chose small branches all above a major wound and tried to choose ones that wouldn't be a problem if removed later.  These were marked with surveyor's tape.

2013 June.  The whole tree is filling out evenly.  I guess that means that strong areas and weak areas have been evened out.

Everything again was thinned and cleaned out.  Overly long shoots were removed.  Places where 3 shoots emerged from one point were reduced back to 2 (to avoid the dreaded "chicken foot" look).  Also old leaves were pulled from woody branches which helps in the look of maturity.  Sacrifice shoots were left long, though on some, the lower leaves were pulled off so they don't interfere with surrounding branches.

 

 I have another plan for this tree that involves turning it to another angle, but it would mean that I would probably have to remove one or two trunks.  It's something I'm mulling over, not deciding anything right now.  Bonsai = living art, the tree changes, and so do we.  That's part of the fun!

 

I hope this franken-tree story has been interesting.  Even "impossible" material can be successfully worked if given enough time and energy.