Japanese Black Pines from Seedlings

I have often been discouraged at the available nursery stock in the Midwest, especially when it comes to some of the traditional species for bonsai. Japanese black pines with  potential are especially difficult to find. Yes, they can be found by the seeker with perseverance,  but inevitably they seem to have insurmountable problems with the nebari and trunk, the two most essential and difficult to change areas of any nursery stock. Twisted and tangled roots, gun-barrel straight trunks too thick to bend and with long distances between branches, and many other problems are encountered with regularity.

The answer to this has always been to grow black pines from seed. Two articles in Bonsai Today (BT 12, BT20) detail the procedure for growing Japanese black pines from seed. For the hobbyist, however, germinating seed and caring for it can be quite time-consuming. Making cuttings of the sprouted seeds and potting these up, then making certain they do not dry out, can be managed, but it sure helps to have a greenhouse with misting system, or to be retired and have several times per day to water the little trees. For the hobbyist who works a full-time job or two, this is extremely difficult.

Recently I hit on a slightly different angle to start with trees young enough to affect their nebari and trunk formation. I purchased 100 Japanese black pine seedlings from a wholesale nursery. They came to me frozen, in peat plugs, one year old from seed. The largest of these were matchstick size. When I received them, I thawed them somewhat and spread the roots as much as possible, nearly bare-rooting them. I potted them up in six inch pots that were a little wider than deep. For soil, I used my inorganic Boon mix for conifers. This mix is extremely well-drained, so I watered copiously all summer long, rain or shine. I actually pruned the roots a good bit, making certain I had the beginnings of a nebari left. I pruned some of the trees and left some of them as they were. In retrospect, I suppose I would leave them all and give them the advantage of stronger growth. With plenty of sun, water, and fertilizer, the trees exploded in growth.

The trees grew well the first year (2003), and I fertilized them with BioGold Original, an organic fertilizer made for bonsai. That year, many of the trees budded twice, putting two years' growth on. By this time, the trunks were the size of a cigarette or a little bigger (left, February 2004). This tree is potted in a six inch pot, and the whole tree is nearly a foot tall, the result of one year's growth. The wire has been applied (see below). On the right, you can see the same tree bent into shape.

The second year (2004), I shaped the trunks with wire. The trunks are easily shaped at this stage. The wire performs a second function in this case, as I let it score the trunk. The more the trunk grows around the wire, the more it swells, adding additional girth. This is why I recommend using aluminum wire at least 3 mm in size. I used a variety of wire, and found that larger wire lets the trunk swell more before it must be removed. I also discovered that aluminum is far easier to remove without injuring the tree. And one further observation: place your coils carefully. Make certain they are close enough together to do the job, but not so close as to cause undue problems. The trees that haven't done much this year are the ones where the wires are too far apart. No pressure is put on the trunk to swell around it.

As the summer drew on, I removed the wire on trees as it seemed the trunk was about to grow around the wire. On a few of the trees, I removed the wire on the upper part and allowed it to stay longer on the lower trunk to cut in more.

The wire, in addition to giving shape to the little trees, will help thicken the trunk, since you are going to let is score the bark a little. Don't worry, the pines tolerate perfectly having the mark the bark, but be watchful and do not let the bark grow around the wire covering it, this would seriously damage the plant. Moreover, since they are young and growing vigorously, the mark of the wire will positively not be noticed later on.  Kusida Matsuo, Bonsai Today 20, pp45-46.

It's amazing to see just how much growth these trees have shown in the short time I have been working with them. The best of them have trunks over 1/2 inch in diameter and some good low branches. Others are almost as big but with fewer low branches or other less desirable qualities. A few seem weak and slow growers. Here you see a couple of the trees with the cutting wire removed. I have since rewired to add movement to the upper trunk. I had wired the trees almost to the tops, and the trees had at least doubled their height!

It's interesting to note that all the trees have developed reverse taper to one degree or another. My hypothesis is that this is normal, since the wire anchored in the soil does not constrict the trunk as much at the nebari as it does further up the trunk. I am confident that with proper root treatment, the nebaris of these trees will expand to fill in the reverse taper.

I was excited recently to find a link to another site that detailed the same technique I have been working on, but with maples as well as pines. Brian Gershuny actually has been doing this longer and has several good pages about his work. He tends to move his trees to a growing bed to accelerate growth, certainly a viable option.

Next spring, however, my trees will go into mesh pots to explode their growth. Instead of plastic colanders as suggested in Bonsai Today, I will be using mesh pots designed for aquatic plants. I will be reporting on this project next summer as results continue to come in.

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