More on differences among Itoigawa, Kishu, and Shimpaku junipers

This is one topic that really intrigues me. Shimpaku has become a favorite bonsai subject, and as I work more with the different varieties, I’ll continue to share the subtle differences.

From macro to micro, here is a little more about each of these three varieties.

My Itoigawa, from Evergreen Gardenworks, and the source of all the Itoigawa material shown.

This is a shimpaku, also from Evergreen Gardenworks, similar in size to the Itoigawa at about 16″.

Finally, the Kishu, which is young, in the ground (left) and growing on. These came from Miniature Plant Kingdom.

Here are some photos of shoots of each variety. For consistency and clarity throughout this post, each shoot will appear in alphabetical order, from left to right…Itoigawa, Kishu, Shimpaku.

These all display mature foliage. Itoigawa is much lighter, brighter green in color. The texture is very fine, and the structure is open, and fanlike. Here is another shoot from the same plant:

The Kishu is brighter than the shimpaku, but the foliage is much tighter, and more succulent than Itoigawa. Many say that the foliage of kishu “balls up”, and in Japan, it’s presently less in favor than Itoigawa. The branches are stout, and the wood seems stiffer than Itoigawa. Here is a photo of a shoot:

And here is a shot from a shimpaku. Interestingly, it seems to be “balling up” like a kishu. Brent sold it to me as shimpaku, so I’m sticking with it. The foliage is a bit ropier in shape, bluer in color, and the texture is somewhere between Itoigawa and kishu.

Now, a look at some individual shoots. Itoigawa foliage reverts from mature to juvenile in response to hard pruning. Looking closely at the foliage structure, it appears that it all starts the same way, but that juvenile foliage extends points from each scale, mature foliage does not exhibit the extension growth, so it appears smoother, and also brighter. The left shoot shows juvenile foliage growing from a mature shoot. The right shoot shows mature foliage extending out from a juvenile shoot. See the difference?

I have yet to get juvenile foliage to grow from one of my kishus, but this juniper from Brussel’s is labeled as kishu, and is full of juvenile foliage. I’m not convinced its kishu.

And here is a photo showing a juvenile shimpaku shoot growing out mature foliage, the blue color of the juvenile foliage is much more apparent in this shimpaku.

Now, some close ups of the “runners” each produces, again, left to right, Itoigawa, Kishu, and Shimpaku:

So, here is a test for you. What kind of juniper is this one?

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Shimpaku and sun exposure

Like many, my first bonsai was a juniper…the procumbens nana, prickly kind with a trunk staked up like a question mark, and the obligatory poodle-like pads. When I started collecting, I moved on to some large, but uncooperative Eastern Red Cedars. It is amazing I came back to junipers at all. Now, more than 15 years later, I’m becoming a big fan of junipers…of the shimpaku variety. Not prickly, and quite cooperative. Yes, they’re very different than P. nana and ERC.

In ’02, I did a Phoenix graft with some shimpaku whips onto old juniper deadwood. Somewhere I have the initial work photographs, but this post is more specifically about sun exposure’s effect on this juniper. The bonsai isn’t great, and hasn’t been a favorite, but I’ve also let it go for a few years at a time, then get froggy and decide to work on it again. Then, it goes back to the back of a shaded bench.

When I actively disliked junipers, this one really got neglected. Always in the back, always in shade, rarely repotted and when I did work on it I’d make some cuttings. The cuttings went into 1-gal cans or in the ground, and I always claimed that my shimpaku did better in shade than in sun.

Of the last two years, I decided to put that position to the test, and am ready to share the results of the 2-year test. And also ready to revise my position on siting shimpakus. Sun has it.

Here is the Phoenix graft, grown in AM sun, and shade for the remainder of the day, with one of its own offspring in the 1-gal orange can, which is grown in 100% all day sun. The cutting is probably 5 years old, and has spent the last 2 years in full sun.

A close up of the foliage:

Both trees are healthy, but the shaded specimen is clearly bluer in color, and not as dense in growth. The tree grown in sun is plumper, brighter, and tighter in growth. Remember, they’re genetically clones. The only real difference is the sun exposure. They’re in the same soil and on the same feeding regimen.

Finally, a shot of 3 shimpakus, from left to right, increasing in sun exposure…from mostly shade (the Phoenix graft) to full sun (the largest of the three). Going forward, I will be keeping my shimpakus in full sun.

One day, maybe one of these three will be ready to show, but for now, they’ve taught me quite a bit about sun exposure and how trees respond to it. Thanks for reading!

A little spring cleaning

Here are a few trees that are in very early phases of bonsai training, and illustrate some good, basic spring pruning techniques, which are essential horticultural skills necessary to set a tree down the right path.

First, a young trident maple. This is the only trident maple on my benches, and it’s deliberately very different from many of the massive tridents often seen. The goal is to develop a very natural, radial nebari, under a scar-free trunk, and a pleasing, open canopy. Ideally, this will be done with relatively little wire. Each year for the last several years, the roots have been worked thoroughly, and when the branching develops a bit further, it will be easily moved into a very shallow pot.

Before pruning:

After pruning:

In order to keep the branching smooth, it is important to stop long shoots from thickening and crossing. Old scars were cleaned up, and shoots were reduced to 2 nodes. I also decided to shorten the leader a bit, because the section had few shoots and no taper. It looks a bit source now, but in a few weeks, we can revisit it.

Second, a cutting-grown cork bark black pine, the cultivar is Hachi Gen. This one has been in a bonsai pot for 5 years or so, and is very slow as a result. One day, it will probably be the right move to shorten the trunk on this and move the second left branch upward to become the apex. For now, the work was to remove all but a dozen pairs of old needles per shoot, and reduce the number of new shoots down to a pair at each terminal. Then, I decandled the tree, removing nearly all of this year’s candles. Light reaching the interior should cause a bit of back-budding.

Before:

After:

Finally, a pair of kishu shimpakus in 2-gallon cans. I started this project for The Alabama Bonsai Society, our Club Tree Project (CTP). We bought 25 junipers, all similar, and allowed members to draw numbers to take home the tree with the associated number. Members can do as they wish with the tree, but document the work…whether they wire, prune, repot; ignore feed and water; or some combination of all. The requirements are simple:
1. We have 2 meetings over the next year where we bring the trees back and share work and results. This gives people a chance to see the results of many different actions all at once.
2. Buy it next spring (dead or alive)…or
3. Bring it back and allow it to be sold as part of the club’s spring plant sale.

We had 21 takers, so I brought home 4 to look after. Here is the first one:

After adding a coarse layer of lava rock underneath, and working in some aggregate on the top. This gives the roots more soil to stretch out into. Plenty of fertilizer cakes were added to the top:

Then, a strand of 5mm aluminum wire was wrapped around the trunk line and the trunk was twisted and “squashed” to create an interesting trunk line. Over time it will be further compacted:

Finally, the last Spring Cleaning project was another of the CTP kishus. This may be the most important pruning technique for a beginner to grasp. Too often, beginners clean out all the growth from the interior of the tree in an attempt to prune, reveal the structure, make it easier to wire, and add a (short-lived) appearance of age. Thinning out the inside leaves all the growth too far out to be beneficial. Instead, prune out the outer foliage, leaving the inner. Next time, I promise better photos…

Before:

After:

Thanks for reading!