This is the first article in a series outlining some of my adventures in ROR (root-over-rock) creation. In this part I start with Brassaia and Dwarf Schefflera; both can grow as epiphytes and show extreme durability and aggressive roots systems; necessary attributes for plants that can naturally survive growing high up on other trees and therefore easily tolerate being grown over rocks.
In the last few months David and the rest of the study group have been educating us on their efforts using rocks to complement and augment bonsai. This type of work in assembling parts is very successful in creating more than the sum of the parts. My experience with rock work has been very basic and primitive by their standards. I only have a few trees that I have placed on or over a rock over the years but I think it may be instructive to potential rock planters to see what mistakes I have made and to learn from my mistakes.
Photo 2. Brassaia growing over a stone, 1989. Photo 3. More development of the tree, roots enlarging, leaves huge! Photo 4. Close up of base revealing only a glimpse of the stone. Photo 5.Brassaia with roots nearly covering the rock
Recent chop back of my Brassaia, original front; possible secondary front, but with weaker basal features
TREE ONE - BRASSAIA 1982-2014
The first tree is a the Australian Umbrella Tree or the full sized Schefflera. It is normally not considered for bonsai as its leaves are huge as you can see in some of the photos. Each leaf has several leaflets and a long petiole and can be over 2 feet long! Not an auspicious looking material for bonsai. But knowing that David has done great work with Brassaia led me to try.
My one and only Brassaia was purchased as two tiny trees with green stems and no mature bark in a 4" plastic growing pot and cost the vast sum of $1. Since the plants were so tiny and insignificant I never took early photos of the trees. Almost immediately after purchase I decided that I needed to create more excitement and dynamic quality so I planted them on top of a stone which was about 8-10" wide and greatly dwarfed the tiny plants.
The plants and roots were not altered or secured in any way but just placed on top of the stone and the stone was sunk into a deeper pot so that the tree's roots were in the soil and the rock was covered as well. The planting date of the tree on the rock was approximately 1982 making this bonsai now about 32 years old. For all these years it has always been in relatively small pots.
Over time and with each repotting the soil surface was scraped off thus exposing a bit of the rock and adherent roots. Any roots that were not on the rock dried up and were removed. Roots that followed the rock contours were saved from drying up by the residual moisture and buffering of the stone.
Looking at the tree in 2014 the rock on which the bonsai is planted is scarcely visible. Unless I point out that the tree is on a rock visitors never realize that there is a stone beneath the roots. Over time the tree has grown, the roots have enlarged, firmly grasped and nearly covered the stone.
The shape of the tree is not as pleasing as I would like and the last pictures show how I chopped this tree back to force branching and growth lower down on the trunk. I am also considering changing the front of the tree.
LESSON ONE: The tree in a root-over-rock design will grow but the rock does not!
So be prepared to remove roots that cover the stone in interesting areas that should be exposed. In addition the tree by its growth will change its relationship to the stone. Your original design may wind up looking quite different from your initial design. Often this is OK as different does not necessarily mean worse.
Another point is that the two trees were seedlings and therefore not genetically identical. The second tree or the one on the back of this bonsai is stronger growing, branches more easily, and has a deeper green leaf color. However its base is not as attractive so I have not thought of it as the front view. I may have to change my mind. When doing multiple tree designs it is best to have the plants genetically identical to avoid one of the materials from outgrowing the other weaker one.
The selection of the rock was not very profound. The rock was about the right size and color but it had really poor surface character. Years later I find the rock I selected to lack character and detail. Plan wisely as the rock planting is often permanent and the rock is not easily changed.
First photo: Dwarf Schefflera over stone with tiny roots reaching to the soil. Next photo: Years later roots bulking up. Third photo: Plant removed from the deep pot. Fourth photo: Planted in a shallow pot to reveal the rock and clasping roots. Last photo: The roots now enlarged and needing a root thinning, considering perhaps lifting the stone and placing it on top of yet another stone to make the planting taller?
TREE TWO - SCHEFFLERA ARBORICOLA - 2002-2014
This tree is actually 3 trees purchase for about $2 and again was perhaps 3-4 inches tall, with no mature bark and just green stems with a few leaves when purchased in 2002.
This group was taken out of its 2" pot and placed on a stone without securing them and planted deeply, covering the roots and the stone in a larger container. Over time the soil was removed exposing surface roots. Over several pottings the stone was elevated to reveal more of the stone and the roots clasping it.
The design is now about 12 years old and still evolving. Over time I will remove more of the roots and show more of the rock. I am also going to see if I can get more branch density. My principal means of doing this is with leaf defoliation, which I do about twice each year.
LESSON TWO: Young roots will mold themselves to the rock when allowed to grow over the stone in this manner.
Older and stiff roots will not mold themselves to the rock easily except when pinned into place with wires, clips etc. Two possible paths exist for utilizing plants for root-over-rock designs. One is to start with plants, often young and having soft and flexible roots. The second it to use older plants with stiffer and often inflexible roots. In the study groups rock plantings, roots are placed into the pre-placed grooves and pinned into place thus assuring a best scenario for the design and not relying on chance alone to get roots to grow into the proper areas.
Developing a long root system depends upon initially growing plants in deep containers, with coarse soil and allowing the foliage to grow wildly without much reduction. Once roots are heavy enough to be used but still relatively easily bent the time is right to make some decisions on the branch design and to plant the tree on a suitable stone.
Start with a well chosen rock; one with great character or build that character in with chisels, drills etc. as the study group has shown.
Two, use well-developed plants with suitable roots for ROR designs. Roots should be long and flexible but yet not too small and thin. Fuku-Bonsai has a great selection of schefflera suitable to ROR.
In the next installment or two I will show other trees and how their ROR designs evolved. Let me know how it goes for you in your ROR work. - - - Jerry "Bonsaihunk" (email@example.com )
Visit Jerry's website at www.bonsaihunk.us