Lack of vigour on Chinese Juniper bonsai.

[Bonsai Phill]

I have had this Chinese Juniper now for about 25 years and I bought it from a specialist bonsai nursery as 6 year old nursery stock, whereby no styling had been done on it and its roots initially being wrapped in sacking. I wired some of the larger branches but still want to wire some of the finer ones. Nevertheless, as the tree has got older, it seems to have lost its vigour and has become rather sparse (see picture). This is despite growing the tree in open ground for a number of years to enhance root development. I have started feeding the tree with Naruko fortnightly during this growing season, and although the tree is looking greener and has juniper berries, there still seems to be no abundance of new growth. It has been like this for approx 3 years now. I have held back k on pruning, in the hope that once new growth has formed, then any subsequent pruning with then increase vigour, but with no obvious new growth to pinch back, I'm not sure what to do. Please can anyone advise?

 

[bwaynef]

Try posting the picture again. Working off the idea that its the juniper in your avatar, I'd recommend getting this tree into well draining inorganic soil. Then situate it in 6+ hours direct sun daily. Keep it well watered and fertilize it in proportion to the amount of growth you're seeing. Start slowly and build up.

Once it builds enough vigor to develop some density, properly cleaning a juniper seems to really speed them up.

 

[Bonsai Phill]

Try posting the picture again. Working off the idea that its the juniper in your avatar, I'd recommend getting this tree into well draining inorganic soil. Then situate it in 6+ hours direct sun daily. Keep it well watered and fertilize it in proportion to the amount of growth you're seeing. Start slowly and build up.

Once it builds enough vigor to develop some density, properly cleaning a juniper seems to really speed them up.

Thanks for that advice, it's really helpful. I'm guessing I'll need to do this in March/April though, am I correct? I'll be looking at repotting the tree then anyway as I feel it needs a slightly larger pot but probably not a root prune, as I did that this year. It would be nice to change the pot to earthenware too.

 

[Bonsai Phill]

 

[Orion_metalhead]

I think there is a great tree in there. Id start with @bwaynef's recommendations as a good start to get vigor back. The inorganic soil element is a major key Ive found.

 

[Wires_Guy_wires]

Plants that have been sulking for a while can sometimes not handle a lot of work.
I think it's wise to grow this one in a size or two larger pot for a year or two.
With the soil adaptations and the extra room, and some extra sunlight, it will probably regain a bunch of vigor.
March or April are good repotting months.

Once it takes off with growth, let that growth run for a year. This increases the chances of budding near the trunk. On the long run, letting it grow wild every couple of years can make a huge beneficial difference.

 

[Calnicky]

You can also try following Harry Harrington's advice about repotting pines, junipers & other conifers in the late summer or early fall. See Harry's species guides here: https://bonsai4me.com/species-guides/. This especially helps when you have too many trees that need repotting ( ...what, who me?) in the spring...but you can shove junipers etc. off until fall.

 

[Shibui]

I suspect there's something going on below soil level that's causing the decline.
As soil ages it deteriorates and starts to clog up the air and water spaces. I find that my trees start to decline after 5-7 years if I have not repotted. In most cases repotting and replacing the old soil makes a big difference in growth and vigour. I don't think a larger pot is the answer though it may help temporarily. If the soil is the problem you need to get rid of the problem.

This is despite growing the tree in open ground for a number of years to enhance root development

Was the garden soil removed when it was transplanted to a pot? Garden soil in pots can be a big factor in decline of potted trees.

I have started feeding the tree with Naruko fortnightly during this growing season,

Does this mean the tree has had little or no fertilizer for 25 years? It can take more than just a few months to recover from near starvation.

 

[Bonsai Phill]

I suspect there's something going on below soil level that's causing the decline.
As soil ages it deteriorates and starts to clog up the air and water spaces. I find that my trees start to decline after 5-7 years if I have not repotted. In most cases repotting and replacing the old soil makes a big difference in growth and vigour. I don't think a larger pot is the answer though it may help temporarily. If the soil is the problem you need to get rid of the problem.

Was the garden soil removed when it was transplanted to a pot? Garden soil in pots can be a big factor in decline of potted trees.


Does this mean the tree has had little or no fertilizer for 25 years? It can take more than just a few months to recover from near starvation.

I was living in Germany for nearly 3 years, during which time my Father was watering the trees for me and sporadically feeding them a liquid 'bonsai fertiliser'. He did no pruning work or wiring though. It was a little concerning though when I returned to the UK that while my other trees needed pruning extensively, this juniper required very little.

 

[Bonsai Phill]

I think there is a great tree in there. Id start with @bwaynef's recommendations as a good start to get vigor back. The inorganic soil element is a major key Ive found.

Thanks for that, and hey, Orion is an awesome track so massive respect there too from one Metalhead to another!!

 

[Bonsai Phill]

I suspect there's something going on below soil level that's causing the decline.
As soil ages it deteriorates and starts to clog up the air and water spaces. I find that my trees start to decline after 5-7 years if I have not repotted. In most cases repotting and replacing the old soil makes a big difference in growth and vigour. I don't think a larger pot is the answer though it may help temporarily. If the soil is the problem you need to get rid of the problem.

Was the garden soil removed when it was transplanted to a pot? Garden soil in pots can be a big factor in decline of potted trees.


Does this mean the tree has had little or no fertilizer for 25 years? It can take more than just a few months to recover from near starvation.

I repotted this tree in Spring this year, so the soil is relatively new, and yes I removed the old garden soil years ago. But you may actually have a point. I was using pre-mixed bonsai compost, so perhaps it may be an idea to mix my soil myself.

 

[Bonsai Phill]

You can also try following Harry Harrington's advice about repotting pines, junipers & other conifers in the late summer or early fall. See Harry's species guides here: https://bonsai4me.com/species-guides/. This especially helps when you have too many trees that need repotting ( ...what, who me?) in the spring...but you can shove junipers etc. off until fall.

Ok thanks for that, I'll take a look at this link.

 

[Deep Sea Diver]

Hmm…

Wouldn’t change the media at all at this point, given the media is relatively new. Pre bonsai compost should be fine at this stage. After considering the information given…. Suspect it resented the repot and perhaps the media is too moist.

Get it in as much sun as possible, 13 hours if possible, in your neck of the woods, monitor watering closely, if too soggy chock one side of the pot up until the media dries more.… and feed the tree up. Solid and liquid. Half strength at first and increase if all is good in a month.

Don’t prune for now. Let’s see how the tree looks in six weeks.

Also, can you please enter the tree’s approximate location and USD cold hardiness zone? Do this by double clicking your icon atop the page, then account details - scroll down and enter these data. This will help us help you better in the future.

Cheers
DSD sends

 

[Orion_metalhead]

Thanks for that, and hey, Orion is an awesome track so massive respect there too from one Metalhead to another!!

Been using this handle since like... 1999 and AOL instant messanger days across all platforms. Ive passed on from Metallica fanboyism but still hold a great respect for Cliff.

I think the overall consensus is get the watering and feeding right. Juniper do not like to be waterlogged or wet. Consistent moisture, but on the dryish side. I water mine once a day in the morning, even in these 90+F temps. I will occasionally hose down the foliage.

 

[Bonsai Phill]

Thanks everyone for your advice. I've been feeding the tree Nuruko sparingly but fortnightly now for a couple of months and it now looks much healthier and is more vigorous.

 

[Deep Sea Diver]

Well done Matey!

Cheers
DSD sends

 

[Bonsai Phill]

Well done Matey!

Cheers
DSD sends

Thank you.