One species that I’m excited to work with over the next few years is sekka hinoki, Chamaecyparis obtusa ‘sekka’.
Sekka are a dwarf hinoki cultivar with incredibly small foliage making them a popular choice for cultivation as shohin.
I have a number of sekka hinoki in one gallon nursery containers that need repotting this year. Here’s the process I follow for repotting them.
Sekka hinoki
I’d like to repot the tree into a bonsai container, but the shallow dimensions of bonsai pots aren’t deep enough for such a tall root ball.
Shallow bonsai pot
In these cases, I can use terra cotta training pots that are deeper than bonsai pots.
Tree, training pot, and bonsai pot
Fitting the tree into the training pot will require that I reduce the root ball. I begin by removing the top layer of soil until I reach the point where the trunk transitions into lateral roots.
After removing the top layer of soil
This reduced the root ball from five inches tall down to four inches. As the training pot is about three inches deep, I now know how much soil I need to remove from the bottom of the root ball.
I also removed some soil from the sides of the root ball which will help me center the tree in the pot. Here’s the tree after removing an inch of soil from the bottom and a little soil from the sides.
After reducing the bottom and sides of the root ball
Depending on how much room there is in the pot, I remove up to half of the old soil. As the pot I selected doesn’t leave much room for new soil, I combed out approximately 40% of the old soil.
After bare-rooting a portion of the rootball
I secured the tree in the pot with two wires (you can see how this is done here), but before I tightened the wires, I worked soil into the area that had been bare-rooted.
Adding soil before tightening the wires
After securing the tree, I filled the pot with soil.
I repotted similar trees last year using an 80% akadama mix. The trees grew well so I used the same mix this year.
Here’s the tree when the repotting was complete.
After repotting – 13″
I keep sekka hinoki in full sun year-round and find that they do well as long as they don’t get too dry. Hinoki produce lots of roots so I expect the tree to be ready for pruning and wiring by fall.