Rocks for Bonsai

Posted by on Aug 7, 2014 | No Comments
Rocks for Bonsai

When I started a batch of Japanese Black Pine seedlings in March of 2006 I had only some inclination of what I wanted to do with them. When the trees were two years old the critical period of determining the eventual style of the tree came. During this time period in a young pine’s life the trunks and roots are still pliable enough to be shaped into almost anything that you can dream up. While I started with a something like 100 seedling pines that year, I quickly realized that potting them all up into larger containers took a ton of soil and time. So I immediately reduced the number somewhat by giving many away; the remaining trees mostly went into pond baskets with a variety of styles.

Of the pine batch, I arranged the young roots of only three over rocks. One larger rock, one medium and one smaller. In each root over rock composition the rock effectively becomes part of the trunk so I should have carefully considered the rocks’ characteristics before using them. The stones will never improve in quality, even amidst all the years of effort that are put into the bonsai.

2006 batch of pine seedlings.   This is a "Napa" field stone from American Soil in Berkeley.   The stones are the same ones I used for my rock wall in my landscape.   They have  minimal texture and are somewhat bland in coloration.   The stone yard says that they are basalt.

2006 batch of pine seedlings. This is a “Napa” field stone from American Soil in Berkeley. The stones are the same ones I used for my rock wall in my landscape. They have minimal texture and are somewhat bland in coloration. The stone yard says that they are basalt. This particular stone is one of my least favorite now.

Taper in a stone is perhaps an odd thing to think about, but consider a couple things before dismissing the idea. The stone will form at least part of the base of the tree in root over rock or rock planting compositions. The visual mass of the stone can have a dramatic effect on the overall feeling of the tree. The taper of the lower trunk frequently dictates the height and overall canopy shape of the tree. So the tree above with roots over the Napa basalt will have to have a short and fat trunk to match the taper of the stone. The entire trunk that is now extending upward out of the photo will eventually be removed in favor of the small bud at the base of the first branch. It will take quite a few years more of development to finish this tree, and when finished the composition will have to be pretty tight to the stone.

2006 Batch of pine seedlings.   This stone is a hard river stone that I picked up a few years ago on a hike.   There is some nice color and hardness to the stone but not much in the way of shape.   Boon says that this is "too angular."

2006 Batch of pine seedlings. This stone is a hard river stone that I picked up a few years ago on a hike. There is some nice color and hardness to the stone but not much in the way of shape. Boon says that this is “too angular.”

The placement of the tree on the stone can make a big difference in the finished product. Generally, we want dynamic looking trees, not straight ones. So planting the tree dead center on the top of the stone is counter productive. Placing the tree to one side or the other of the stone will allow the roots to trail over the top as is the case with the river stone and pine above. The base of the tree is on the left upper edge of the stone and the largest root moves over the stone and then down the right side.

2006 batch of pine seedlings.     This particular stone may end up being the best attempt of my first batch of pines.   There is some good texture in the stone and a little color variation.   The tree is hugging just the right side of the base, not the top of the stone.

2006 batch of pine seedlings. This particular stone may end up being the best attempt of my first batch of pines. There is some good texture in the stone and a little color variation. The tree is hugging just the right side of the base, not the top of the stone.

The texture and color of the stone seems like it needs careful consideration to match the trees bark and characteristics, just like selecting a glaze container to go well with the foliage or bark color of a tree.

2009 batch of Trident seedlings.    This is the only one of the ten that I have remaining that is over a stone.  Unfortunately, the texture and color of lava stone is not particularly interesting.    I can't remember why I chose this stone in particular, but there's not much hope of changing it.    In most Japanese Trident over rock compositions I've seen the stone is usually dark in color, with  a very irregular pattern and texture.

2009 batch of Trident seedlings. This is the only one of the ten that I have remaining that is over a stone. Unfortunately, the texture and color of lava stone is not particularly interesting. I can’t remember why I chose this stone in particular, but there’s not much hope of changing it. In most Japanese Trident over rock compositions I’ve seen the stone is usually dark in color, with a very irregular pattern and texture.

2009 Batch of Trident maples.   The tree is well established on the stone.   From the current front the stone has a relatively minimal role in the composition.

2009 Batch of Trident maples. The tree is well established on the stone. From the current front the stone has a relatively minimal role in the composition.

The trident above is not well-matched to the stone in my opinion. But there’s nothing to be accomplished by ripping it off the stone in favor of another. Onward and upward! The next batch will benefit from this contemplation of details.