Four views of the "welded splatter" rock before sculpturing. This came from a different cinder cone where larger blobs of lava was thrown up but because they fell in rapid succession, various layers are formed and the material is less fragile and more tightly fused together that the previous example.  The rock was 19" long, 71/2" thick, and 13" wide and weighed twenty-three pounds before any sculpturing.  Top left photo shows the material in it's natural position and roughly the orientation if to be used in a horizontal position.  Generally we would flatten the bottom (taking more off from the left side) to create a slightly steeper ledge.  A planting area would be off-center right (into the larger mass of the rock)  with additional detailing to enhance the ledge-like formation.  Top right shows the bottom,  left bottom shows the back, and bottom right shows the top of the rock.


            Every rock is different so this is a second example of vertical rock sculpturing that are inspired by the sheer Koolau cliffs on the windward side of the island of Oahu where I once lived. Rocks like this one are too large for even our large size Hawaiian Lava Planting and are destined to go into our Custom Collection where every creation is an individual effort and individually priced.  I tend to prefer vertical arrangements for larger rocks rather than horizontal for two pragmatic reasons: 

         1.  A lot more sculpturing is involved and it helps to reduce the shipping weight of the finished bonsai.  It is also possible to utilize smaller bonsai containers which also reduces weight.  But it makes it more feasible to use round containers with turntable hardware so the arrangement can be easily enjoyed from all sides. We are designing and will be producing larger round pots for such larger Custom Collection vertical rock plantings in the future.  Although we already have extended root trees that are five to 20 years in training, it will take several years to fully establish them on the rocks.  Larger vertical rock Custom Collection will be relatively expensive due to the time and work involved.

         2.  True Indoor Bonsai are intended to be displayed indoors and in most homes,  there are limited number of places suitable for displaying such trees.  Most homes are just too crowded with not enough plain background display space.  An aged, low, wide, heavy-crowned banyan bonsai may be 18" tall but 36" wide and spectacular in an outdoor bonsai garden.  But if you use the guideline that there should be a clear background equal to the width of the bonsai on each side,  you would need a nine feet wide plain background that is not generally available.  But if instead the bonsai were 18" wide x 36" tall,  it would be much easier to have a four and one half feet wide plan background.  Indoors,  narrow tall bonsai with a lot of character are impressive indoors!  



         Figure out how the rock will be best positioned by studying and creating a plan that shows its best features in the finished product.  The bottom was cut near its widest point at an angle so the two rock seams would be as vertical as possible. I prefer to use a specially made light hardened steel pick for my rock sculpturing work. Multiple hits along the intended cut-line slowly increases the depth of the cut until it breaks where I want it to.  I'm usually successful over half of the time, and when it breaks at the wrong place, I come up with a "Plan B!"

          This time the cut came out where I wanted it and the large section was turned to show the bottom.  This reveals the "grain" of the lava, and once you learn how to read it,  you pretty much know what you can accomplish. This is a high potential rock with an interesting grain pattern to allow attractive shaping of all sides. 
         Visually sight the bottom and make small chips so the rock sits solidly.  To further smooth the bottom, it's rubbed back and forth on a hollow tile block. 
         Start by creating the top-most pinnacle.  In this case I wanted to repeat the slant of the left side onto the right side and needed to remove a protruding section.  Carefully chip increasingly deeper grooves around the section you want to remove.  Flatter rocks are easier and when sculpting our Hawaiian Lava Planting rocks, the staff use rock chisels as well as the steel picks. 

        To now,  I do most of the Custom Collection rocks and prefer to use the steel picks and only utilize the choice selected rocks that have more character.  

         Again the section removal was successful.  Note that the rock has two colors.  The red color is usually surface lava whose outer edge is a harder "glaze" for about 1/4" with softer interior.  The other brown-black color is interior lava that have larger air holes and sometimes dense hard rock veins.  It takes a lot of experience to judge how to show off the best features of the rock.  Rock sculpturing is hard work, but very satisfying.    
        The next three photos show how one side of the rock was shaped.  Start at the top to create the first pinnacle and in cutting the steep cliff,  a small valley is created and second and third pinnacles are being formed.  
          Continue to shape the pinnacles, moving the valleys deeper and dropping down,  imagining how waterfalls would form in tropical storms that would cut the valleys steeper and deeper.  If the water hits a hill, it would split the waterway into two valleys and a new "pinnacle saddle" would be formed. 
         In creating pinnacles,  try not to have the tops at the same height.  Where there's a long drop from the top to the bottom, imagine a waterfall dropping right into what can be the "ocean!"  Where the rock ends in mid-air, imagine sloping media filling up that void.  Or place a similarly shaped rock a bit away and fill in the area with potting media. Visitors came,  took workshops, I addressed other issues and I wasn't able get back for several days.
         The rock was trimmed to reduce the bulk, deepen the valleys, and sharpened the pinnacles.  The small section chopped off earlier was shaped into a complimenting formation.  Yellow markers predict a three tree planting. 
         It's time to stop and consider the health of the plants.  With strong roots, the valleys were bore out to provide catches for a generous supply of on-demand Nutrient Granules.  Knowing where the plants will be allows boring out valleys that will be concealed.
         Keep watching out for the portions that will be exposed and reduce the mass to reduce the weight as well as create a better environment.  This type of lava is very easy to sculpt and is used for our Hawaiian Lava Plantings.  The rock is hard enough to not easily break as roots expand. If the rock cracks, use a conversion kit and pot it with roots going into the pot.
          SELECTING THE PLANTS .   While the concept was a vast panoramic cliff scene,  I follow penjing concepts and switch scales when appropriate.  I switched to a closer scene where three trees grow on large rocks.  Two 8LS8 Roots were selected for the main rock where their crowns would blend. a large crown of a single tree.  A smaller 4LL8 Roots was selected to be planted on the smaller added rock.
           COMPLETING THE ROCK PREPARATION.  Holes were drilled and a heavy wire ran down through each valley that would have roots.  Paper covered thin bind wire would hold the roots in and form a network near the surface to hold the sphagnum moss on the outer edges.  By dibbling in media deep in the valleys, it would push the roots outwards to be seen and the sphagnum moss and the bind wire network would hold everything in place and roots will grow vigorously down into the pot. 

          Near the bottom, holes were bore through the rock to allow securely anchor the rock to the pot. During the planting, these wires are coiled out of the way and the rock is locked in when the planting is almost finished and before the media is added to the pot. Rock plantings and forest arrangements are considered the most difficult forms of bonsai.  In addition to planting techniques, it is also necessary to learn detailed pruning and cultural techniques to keep the plants healthy.  

           CREATING THE "SADDLE."  I prefer not to plant on the very top of the rock as I consider it unnatural.  The tops of rocks don't collect debris and seedlings would not grow there.  But there are exceptions. First stash away Nutrient Granules. Cover with sphagnum moss and body media, more sphagnum moss, body media until the "cushion" is 1" to 1/1/2" thick.  So when the plant is placed on it an pulled down with wire, the tree will sit firmly and appear to be solidly anchored to the rock.  
           PREPARING THE TREE.  The side of the tree with the best branches will face away from the rock.  So on the other side, open up the root ball, removing some surface roots and any large roots under the main trunk.  Spread out the roots so it will sit on the cushion in the saddle.  Pull it down hard and anchor with multiple bind wire that will rot away without hurting the tree. By the time the wires rot away the tree will be establishd. 
         The photo shows the largest tree mounted, the roots divided into valleys to travel down to the media in the pot.  Although the roots only came halfway down the rock,  because I selected "Roots" trees, it was far easier than if I selected "Sumo" trees that did not have roots extended.  Sumo trees also have strong surface roots the extend outwards.  So they are okay for our flattish Hawaiian Lava Plantings but not for vertical "Root-over-rock" designs. 
          Once the tree is anchored, lay the rock flat and fill the valleys with first Nutrient Granules, moss, media, until almost all of the valley is filled.  Then create the network of bind wire.

          The photo shows the second tree being prepped.

          This photo shows the second saddle and the second tree.  A few more surface roots were later removed to fit the tree more naturally into position on the rock.  In this type of planting, you want the roots to be a visual extension of the trunk and trees that are pre-trained into "Roots" are ideal.  These 8LS8-R trees are about 8 to 10 years in training.
           The first two larger trees in position.  Although they appear to be the same height, the larger taller right tree is on a saddle about 2" higher than the smaller left tree.  Later in trimming, a composite crown will be developed made up of branches of both trees. 

          Note that there's a number of bind wires positioned both from the top and from the bottom. The bind wire forms a network to hold the sphagnum moss on the surface to hold roots in place.  So when you compress and dibble media between the roots and the rock, it tightens everything up. 

          If you hadn't seen the deep valleys before the trees were planted,  you would not be able to guess how much media has been stashed away!  The generous amount of sphagum moss serves as a water channel to keep the plants healthy.  Load up sphagnum moss between the trees and the rock.  When watering, water this area well and the water will go down between the tree and the rock.  It will be impossible to water to penetrate if it had to go through the roots on the surface. 

         View of the near finished arrangement side #1 with the smaller companion tree on lower back rock. The gap between the two rocks is filled with media.  This view has the tallest tree facing the front and the second large tree on the right side.
         View of the near finished arrangement side #2 with the smaller companion tree in a front right position.  The tallest tree is now on the right and facing the back while the second tallest tree is facing the front.  Tropical trees tend to create what appears to be a common crown.  But when viewed from different angles,  there is all the variety that you'll see when trees grow naturally close together.
          This view of the crown take from off to the side shows the separation of the two trees. The heavier and higher structure of the largest left tree and the now pruned second tree. 
           If the planting is left unprotected, some of the media in the valley will wash out.  So some crumpled foil is position to protect the valleys with a little dibbling in along the edges.  Where there are protected areas near the top,  narrow monofilament tape help to support the foil.  When all foil is in place in all valleys that contain roots and media, an overall crinkled foil wraps around and holds all in position to allow watering without having to be excessively careful.
            The completed arrangement with the temporary protective foil.  Note there are larger 1/4" holes to provide air circulation between the foil and rock. Without the outer foil, the individual valley foils will fall out.  The foil will be left on until the fine root hairs cover all the sphagnum moss and this may take six months or so.  After root hairs develop, larger roots (about 1/16" in diameter) form, and after that still larger permanent roots 1/8" and larger develop.  These larger roots can handle been exposed to direct sun.  So the foil will need to protect until the larger roots form in a year or so. 
  ***  Return to the November 2013 issue of Journal of Tropical & True Indoor Bonsai
  ***  Go to Mid-Pacific Bonsai Foundation website
  ***  Go to Fuku-Bonsai website
           Mid-Pacific Bonsai Foundation and Fuku-Bonsai, 2013