A few months ago I started a number of shimpaku cuttings. Several different soils were scattered around the workshop so I tried some of each to see if it made much of a difference.
I did a similar experiment several years back and found a huge difference between soils (see “Shimpaku cuttings” for details). This year I tried bonsai soil – a 1-1-1 mix of lava, pumice and akadama – kanuma, pumice mixed with mulch, and fines from Clay King mixed with pumice.
The kanuma seemed like it would offer a good mix of air and moisture, and for the most part it did. Eight of the ten planted are doing well.
Shimpaku cuttings in kanuma
The bonsai soil performed similarly, with eight of ten surviving. The particle size was between 3/16″ and 1/4″ – what I typically consider to be a small-sized mix.
Juniper cuttings in a mix of lava, pumice and akadama
As I sift all of the soils I use before repotting, I tend to have a lot of fines lying around. I knew the drainage would be good so I tried a mix of 2 parts Clay King fines and 1 part pumice fines – approximately 1/16″ – 1/8″ in size.
Clay King fines with pumice
I was surprised to see that all of these cuttings took. I’ve used a similar mix for pine seedling cuttings for years but will now use it as a general purpose propagation mix.
What didn’t work? Pumice mixed with mulch. Just two of ten planted cuttings took – results similar to the last time I experimented with organic matter in the mix.
Poor results – pumice and mulch
I’ve used this mix for older specimens of different varieties and find it can work well, but I don’t plan to use it again for cuttings.
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Well done! Thanks for sharing your experiences!
Did you use any rooting hormone on this experiment?
Jonas Dupuich says
Great question Mark, thanks for the reminder. I usually use liquid or powder hormones, but didn’t for this experiment as I was curious how the cuttings would do without it.
Hannes Fritz says
Good day ..what time of the year do you do your cuttings?
Jonas Dupuich says
Hi Hannes – for junipers, I take cuttings all year long. If it’s cold out, I’ll keep them in a greenhouse, otherwise I leave them outside.
Ron Smith says
Great experiment Jonas, I’ve tried everything but the kitchen sink in the past 40+ years, but never Kanuma. You never fail to amaze me.
I’ve used 50% Kanuma and 50% Pumice together in Houston to reduce the water retention level in azalea soil mix. Thanks again for your willingness to share information. Ron