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!
Nebari Bonsai 
While I’m sure that you are correct about the sun exposure, I’m thinking that the pot that the tree is in has a bit to do with it as well. I find that pots that dry out faster on water loving trees, even given the exact same circumstances can slow that tree down. I know that these are more dry loving trees, but I wonder if pot heat has a factor. What do you think?
Thanks for the comment Judy. Interestingly, both subjects are in plastic pots. Neither is getting really hot, but the one exposed to more sun grows better. It does dry out a bit faster, but watering is pretty consistent between them.
The middle one is in ceramic pottery, and I’ve been increasing it’s sun exposure, and it is looking stronger all the time.
Interesting study Brian, thank you for your results. That shot of the foliage is really telling the story. Interestingly enough, I don’t think my shim souks get enough full sun and they look similar to your phoenix graft.
Reblogged this on Wolf's Birding and Bonsai Blog.