Conflicting hard prune info.

[Mike Corazzi]

The BSSF (Bonsai Society San Francisco) handout chart shows NOW as time to hard prune juniper.

That is the ONLY place I see that reco. ALL the google searches say spring.
Which would be right for Zone 9?



That pic SAYS it's a ...small... pic.
????

 

[MaciekA]

On the one hand, in zone 9 the difference between now and spring is on the one hand negligible, because winter is super mild either way, whatever happens. The "metabolism time distance" between now and spring if measured in July days is probably hardly even 1 July day. So in theory the two dates (now vs early spring) are from the tree's point of view mere moments apart, time is very slow for that juniper now. So the main consideration in my mind is frost risk due to wiring.

So on the other hand, by spring time, that juniper will have accumulated more sugars into its wood and have most frost risks now well behind it. If you heavy prune and wire in one go (I almost never prune unless I'm also about to wire, because I want to put dormant buds / buds / interior into their new positions), then you may desire less risk of branch loss. Frosts are a risk to recently-wired branches. If you're an expert wirer or have a shelter shed / greenhouse then maybe that's a non-issue for you and what you'd rather do is use an available weekend in November/December to get this done instead of waiting.

On the other-other hand we're in a strong or "super" El Niño, so you may not get as many frosts going forward, especially past solstice where El Niño exerts its primary influence. If that was the case and Lincoln got a super mild winter, then it all really comes down to whether you want the tree to continue to bulk up and accumulate sugars (albeit at a glacial speed in summer growth rate terms) prior to the heavy prune. Whatever the case, early spring is objectively safer and means a slightly more bulked up tree (that bulk would come in handy for the response growth).

At my teacher's garden and in my own collection I've done these heavy prunes in mid summer.

Side note, you may want to either get an updated handout from BSSF or ask the people who produce that handout to update their knowledge on fertilization. I recommend Michael Hagedorn's Bonsai Heresy, which busts the myth of 0-10-10. In the spirit of Gell Mann Amnesia, it would be hard for me to trust anything else written on a handout that stated 0-10-10 myth a recommendation.

 

[Shibui]

I have no problem hard pruning junipers in autumn in equivalent of zone 9b. I work on junipers year round with the exception of avoiding hard bends in the spring growing season.
Conifers are active year round here. Though growth is still negligible through what we have of winter, the trees do respond to light fertilizer through winter with increased growth in spring.

 

[Mike Corazzi]

SACRAMENTO chart shows same.

Think I'll just wait.

 

[Potawatomi13]

Watching Ryans Sierra(?) Juniper live steam this eve depends on kind of Juniper.

 

[Bonsai Forest]

SACRAMENTO chart shows same.

Think I'll just wait.

View attachment 519120

I am 7b, Charlottesville VA. Agreeing with Shibui. I have 3 healthy JPN’s. Pruned crotch growth (including directly bottom growth and directly vertical growth on top side of branches) at the end of Spring, Summer, and Fall. End of Fall was structural pruning removing selected branches, and performed structural wiring. Mine are still in development, receiving 10-10-10 in March and September with additional N via H20. All doing well.

Josh Hooson, from Australia, recommends this for Junipers:

 

[littletreefarmer]

I've found myself seeking the same advice recently and coming back equally confused.

I think I've decided my plan for 2 large Shimpaku I acquired this Autumn will be to perform hard, major cut back late this winter/early spring before growth really kicks off, and possibly even performing structural wiring then. I will, however, allow the trees to grow freely for the season, and perform another cut back of strong growth in autumn. These trees are already growing very vigorously and were planted in bonsai containers by the previous owner but never pruned, so they have far too much branching. I would have done the cut backs in autumn and wired in spring, but I didn't purchase them until October, so I thought it was too late already.

 

[Bonsai Forest]

I've found myself seeking the same advice recently and coming back equally confused.

I think I've decided my plan for 2 large Shimpaku I acquired this Autumn will be to perform hard, major cut back late this winter/early spring before growth really kicks off, and possibly even performing structural wiring then. I will, however, allow the trees to grow freely for the season, and perform another cut back of strong growth in autumn. These trees are already growing very vigorously and were planted in bonsai containers by the previous owner but never pruned, so they have far too much branching. I would have done the cut backs in autumn and wired in spring, but I didn't purchase them until October, so I thought it was too late already.

Wiring Shimpaku in Spring makes sense in my mind since they're such slow growers and less likely to swell, grab onto, and bite into branches as a JPN might do.