Shimpaku cuttings from a weak tree.

[GrampaMoses]

Hi, so I've had this shimpaku juniper for a few years now and it's always struggled. In 2020, I repotted into a deeper pot and moved it to the sunniest spot in my backyard. I suspected it had spider mites and treated it for that. In 2021, I let it grow untouched and it now has several long shoots that grow past the silhouette of what I'd like my bonsai to be.





My assumption is that the shoots have done their job and I can now remove them and grow them as cuttings. I can see where stem turns from green to brown and was planning to cut to include 3 inches of brown stem, removing the lower foliage, and putting that in the growing medium of my 4 inch deep propagation cells.

What I'm not sure about is growing medium for these cuttings. I have akadama, lava rock, pumice, DE, and pine bark fines. I'm also not sure if this is the best time to make the cut (first day of fall and it should be cooler and rainy for the next week) or if I should wait for late fall. Ohio winters are harsh, but I have a cold frame to store them in until spring.

Any other thoughts or tips would be appreciated. Even though the new shoots are green and healthy, I'm still seeing foliage turn brown and fall off during the year, but I didn't see any signs of mites this year. The tree is in the sunniest spot of my backyard and planted in DE, pumice, lava.

 

[Brian Van Fleet]

I’d wait until spring, when the tips brighten up again. Make cuttings like shown by red marks. Pine bark fines and lava rock about 50/50 works. I don’t use rooting hormone for Shimpaku. Keep them in the shade, mist regularly, and by next fall, you’ll know how many survivors you have. In Spring of 2023, twist them up and plant them out.

 

[Shibui]

Those shoots look healthy and strong so should root well.
You can strike mini cuttings as shown above and get lots of little trees but they will take some years to grow to usable size.
I strike the entire stem up to 12" long. That way I already have a trunk long enough to wire and bend as soon as it has roots.


I put in shimpaku cuttings any time of year (note our winters are not cold). Roots can be very slow over winter but the cuttings stay alive for up to 2 years so eventually you should get some to root. Roots happen quicker in spring and summer. Given Ohio winters maybe you would be better to wait until spring to strike these cuttings.
I also use hormone on shimpaku cuttings. Now that I see @Brian Van Fleet strikes successfully without I will be interested to do a side by side test with and without next time to test whether it makes much difference.

What I'm not sure about is growing medium for these cuttings. I have akadama, lava rock, pumice, DE, and pine bark fines. I'm also not sure if this is the best time to make the cut (first day of fall and it should be cooler and rainy for the next week) or if I should wait for late fall. Ohio winters are harsh, but I have a cold frame to store them in until spring.

My cutting mix is 50/50 perlite/coir peat mix. Any mix that is free of disease, holds some moisture but plenty of air is fine. Peat/sand is traditional. Akadama, pumice, DE should all have reasonable properties for cuttings either alone or in some combination. Like bonsai soil, most propagators find a mix that suits the way they grow in the local conditions so everyone will have their own mix.
Probably stay clear of pine bark unless you can sterilize it as it may host fungi and other pathogens.

Any other thoughts or tips would be appreciated. Even though the new shoots are green and healthy, I'm still seeing foliage turn brown and fall off during the year, but I didn't see any signs of mites this year. The tree is in the sunniest spot of my backyard and planted in DE, pumice, lava.

Older foliage turning brown is an annual event and perfectly normal. Even though juniper is evergreen individual scales only have a 2-3 year lifespan and will die after they are worn out. Our challenge is to retain some inner foliage to cut back to when the outer shoots are too long.
Entire shoots dying can be due to lack of light. Weaker inner shoots are particularly affected. Poor nutrition and/or watering will make shoot loss worse as the tree struggles to maintain some limited foliage with scarce resources.

good luck with both the parent tree and the cuttings.

 

[GrampaMoses]

Poor nutrition and/or watering will make shoot loss worse as the tree struggles to maintain some limited foliage with scarce resources.

Ah, yes. I was not very good about fertilizing this year and only used a slow release once in Spring.

Thanks to you and Brian for your thoughts.

I have an unheated (but attached to the house) garage with a woodworking bench that I put my less cold hardy trees on. I might take a few cuttings now to over winter in the garage and a few cuttings in spring as the tree breaks dormancy. Use it as a learning experience for me and my climate.