Growing pines from cuttings

[Shibui]

I've tried all times of the year but not enough to be able to give reliable data on what strike rates for different seasons.
One of my original informants swore that there was a limited window in late winter/early spring but I've certainly had success outside that narrow time.

Cuttings of other species seem to root OK at different times of the year if you can provide the correct conditions. With some species I've had better success with Fall hardwood cuttings. I suspect the dormant period gives them time to callus and get ready to grow roots before having to support leaves. Can't see why that will not work for pines too so I'd encourage you to have a go. Look forward to hearing the results.

 

[Manbris]

Hi @Shibui - this is really great work and I have just tried to do similar here in Yorkshire. This year we had driest spring on record- just recently we had some good rainfall. I fertilised heavy two weeks ago. Last pic is the one of the mother tree- it is strong. The other mother tree is a 3 year old seedling with relative strong growth.

Two questions-1. I cannot decide a final position for the cuttings- I placed them on top of scots pine seedling pots facing east? or should I place them on the concrete slab or in a shed nearby? 2. I dipped them directly in the growth hormone bottle...would it ok?

Thanks!

 

[Shibui]

Cuttings generally require high humidity to survive long enough to grow some new roots. Maybe Yorkshire ambient humidity is high enough but I doubt that. Mine are all placed under intermittent misting. Second best would be plastic domes or bags over the pots to maintain humidity around 90-100% until new roots can form and give water to the cuttings.

A couple of other growers have reported they are able to root new candle growth but I've never had success with new shoots. I've only ever successfully struck 1 year old shoots and juvenile shoots from young seedlings. Occasionally, older seedlings will produce juvenile regrowth after hard pruning which will also root easily.

Most rooting hormone is used at the strength supplied so full strength is correct usage but dipping your cuttings into the original bottle will contaminate the mixture and it tends to go off rather faster than it should. Better practice is to decant some into a separate container and dip into that so the remainder in the original container will last longer.

 

[leatherback]

@Shibui do you use bottom heat? Or is ambient temps so high when you take them that hat would be overkill?

 

[CapeCodBonsai]

I only grew cuttings because we could not get seeds here.

It seems like it’s hard to find viable Japanese White Pine seeds (Pinus parviflora) in the U.S. lately. I’m lucky enough to have a couple that I started from seed a few years back. I’d love to get a couple more. Maybe I’ll try cutting propagation next time I’m trimming them up. Thanks for sharing the info!

 

[Shibui]

@Shibui do you use bottom heat? Or is ambient temps so high when you take them that hat would be overkill?

I've never used bottom heat.
Initially because we lived off grid so no access to suitable electricity. Toyed with all sorts of alternative systems but never got around to implementing any. Most cuttings seem to do well enough without, so I have not bothered, even since moving to the new property and the luxury of mains power.
My understanding of bottom heat is that cuttings do better when the base is warmer than the top (regardless of ambient temps) rather than simply raised temps. That's why propagation uses bottom heat rather than top heat.

 

[MaciekA]

There are some academic experiments on pine (contorta specifically) that show that if the above-soil ambient temp is relatively high (20C) and the soil is also warm, then the tree actually focuses on foliar growth. I assume this is why "top cool bottom warm" is the propagator's preference.

In these same experiments (again w/ p contorta), when the ambient is warm (20C) but the soil is cold (i.e. below 10C, I think the experiment was around 5-6C), then the products of photosynthesis instead go towards nonstructural carbohydrates (i.e. stashing starch, but in pine this naturally means buffing up the roots / expanding callus / etc). So for summer propagation the right move for pine might be a relatively warm ambient combined with a cool soil. I've only ever used heat mats in the cold seasons and these experiments have made me wonder if the ideal dream setup for summer conifer propagation might involve an actively cooled (perhaps w/ water?) soil setup or perhaps with clones sitting directly on the ground. Depends on local conditions though, around here our water supply is quite frigid even through summer. I can think of a few garden setups I've seen where 20-25C ambient w/ much cooler soil (closer to 10-15C) could be achievable and perhaps make pine cloning easier.