Itoigawa

[Daluke]

I sprayed with copper fungicide.

There’s some species that just don’t make it in particular hands - itoigowa may be mine.

Hopefully yours pulls through.

[PeachSlices]

my biggest one same thing one branch went brown then whole tree died slowly

your not alone, might be just winter colouring aswell

Simon

[SuperBonSaiyan]

my biggest one same thing one branch went brown then whole tree died slowly

your not alone, might be just winter colouring aswell

Simon

How do the Japanese prevent this from occuring on their older trees?

I know there's preventative spraying, which I've been doing (lime sulphur in winter, rose shield throughout growing season).

I guess I just need to add a stronger (copper and or mancozeb) spray to my Itoigawa throughout the year as well?

[Daluke]

my biggest one same thing one branch went brown then whole tree died slowly

your not alone, might be just winter colouring aswell

Simon

How do the Japanese prevent this from occuring on their older trees?

I know there's preventative spraying, which I've been doing (lime sulphur in winter, rose shield throughout growing season).

I guess I just need to add a stronger (copper and or mancozeb) spray to my Itoigawa throughout the year as well?

Probably a combination of all and;

Clean benches and tools

Good fertilisation for health and vigour

Space between trees to prevent overcrowding

Grow trees that do well in your environment

I guess if trees are able to grow old, they have some genetic vigour.

In my veggie patch the things that grow from seeds in the compost always do better than seedlings. It’s like they had a disposition to survive.

[SuperBonSaiyan]

A nice Itoigawa (grafted onto a collected tree) I came across in my browsing.

I like that this tree shows some branching in the crown and not just foliage. I imagine this would be difficult to accomplish in a smaller tree.

Also really like the movement in the deadwood.

[SuperBonSaiyan]

If you want junipers to thicken as quickly as possible in the ground (or pots) don't grow them in soil or potting mix, grow then in quartz sand beds around 8 inches (20mm) deep with maybe 10% organic mixed in. The sand should be a mix of 0.5-4mm particle size. They will respond to that quickly.

I've potted up a few junipers with your suggested sand mix.

Could you give info/tips about watering? Because sand doesn't change colour when wet, how do you go about watering junipers in sand?

When I repotted one of your junipers the roots were fantastic, so I know it works. Just want to make sure I water correctly.

Also, would this sand mix work for pines?

[Keep Calm and Ramify]

grow then in quartz sand beds around 8 inches (20mm)

For those of us who don't know inches - I think Treeman means 20cms deep - not 20mm.

[treeman]

I've potted up a few junipers with your suggested sand mix.

Could you give info/tips about watering? Because sand doesn't change colour when wet, how do you go about watering junipers in sand?

When I repotted one of your junipers the roots were fantastic, so I know it works. Just want to make sure I water correctly.

Also, would this sand mix work for pines?

If they are in an airy place in full sun, like mine, water every day in summer along with everything else. If you have just repotted, they will take a while to dry out, especially this time of year. Use the finger in the mix technique. if moist, no need to water. Junipers are very drought tolerant, especially if they get daily dew or misting. But of course they grow faster if well fed and watered.

[SuperBonSaiyan]

I have an Itoigawa that's doing a bit poorly compared to the others.

Happy to report that this plant now seems to be doing well. Pushing out new growth from the tips (healthy light green).

I've still kept it isolated - when should I re-integrate it with the other plants? (leave it a few more months or is it safe to do so now?)

Fix ended up being to spray with Mancozeb and cut off all the bad (infected) branches & foliage.

[treeman]

If you want junipers to thicken as quickly as possible in the ground (or pots) don't grow them in soil or potting mix, grow them in quartz sand beds around 8 inches (20mm) deep with maybe 10% organic mixed in. The sand should be a mix of 0.5-4mm particle size. They will respond to that quickly.

[SuperBonSaiyan]

If you want junipers to thicken as quickly as possible in the ground (or pots) don't grow them in soil or potting mix, grow them in quartz sand beds around 8 inches (20mm) deep with maybe 10% organic mixed in. The sand should be a mix of 0.5-4mm particle size. They will respond to that quickly.

I've repotted all my plants now, most of the developing junipers in sand, like you suggested.

My question was more around when to put the Itoigawa in question back onto the benches. It's kept isolated so it doesn't infect the others, but I'm not sure how long to keep it isolated to be safe.

[treeman]

My question was more around when to put the Itoigawa in question back onto the benches. It's kept isolated so it doesn't infect the others, but I'm not sure how long to keep it isolated to be safe.

Sorry that was not a reply, just fixing an old spelling mistake.
It should be fine to put it back on the benches. This disease does not seem to be that contagious as I've had sick and healthy ones side by side without much change. I think the disease enters through a wound made either by scissors or by some kind of insect. I don't really know much about it's spread. Whether it is directly (sap to sap) or by wind-borne spores or both. So regular spraying would help - not that I do it..... Interestingly, grafted shimpakus seem more resistant to the disease but that is another unproven hypothesis. I might try grafting some more Ito onto procumbens or Kaizuka and see how they go.....

[SuperBonSaiyan]

My question was more around when to put the Itoigawa in question back onto the benches. It's kept isolated so it doesn't infect the others, but I'm not sure how long to keep it isolated to be safe.

Sorry that was not a reply, just fixing an old spelling mistake.
It should be fine to put it back on the benches. This disease does not seem to be that contagious as I've had sick and healthy ones side by side without much change. I think the disease enters through a wound made either by scissors or by some kind of insect. I don't really know much about it's spread. Whether it is directly (sap to sap) or by wind-borne spores or both. So regular spraying would help - not that I do it..... Interestingly, grafted shimpakus seem more resistant to the disease but that is another unproven hypothesis. I might try grafting some more Ito onto procumbens or Kaizuka and see how they go.....

I noticed some of my Itoigawa foliage was yellow.

1 (5).jpg

Is yellowing of the foliage an early indication of disease? Or is it something normal for this time of year?

When I receive my Itoigawa plants from you, they're always a healthy lime green - then over time the interior foliage yellows and falls off for me. So you must be doing something I'm not... Or I'm doing something wrong? Hoping you can help me pinpoint the problem.

The pictured plant is in primarily sand with minimal (10-20%) pine bark mixed in. Top dressed with sphagnum moss. Fed with dynamic lift + blood and bone in the teabag + a fortnightly drench of charlie carp and sometimes seasol. Kept well watered (once a day, then misted when the sphagum top dressing dries out). Kept in full north facing sun. Alternating spray monthly with rose shield and mavrik.

[SuperBonSaiyan]

I can't seem to edit my post, but I think I found the answer from Bjorn:

Additionally, juniper bonsai will likely shed interior foliage as the temperatures start to heat up in summer. This yellowing growth is referred to as toya in Japanese. This is a normal process wherein the tree is shedding weaker foliage in favor of stronger external foliage to help offset over-transpiration. In order to limit the amount of toya produced by a juniper bonsai, consider removing some growth from the tree earlier in the Spring season. For example, remove foliage on the undersides of pads, as well as crotch growth and unnecessary branches in the tree's design. Once again, though, be sure to leave the extending shoots intact and uncut at this point in Spring.

https://www.bjornbjorholm.com/care-and- ... juniperus/

[treeman]

Yep all normal.
I do notice you are getting algae growing on the surface of the p/mix. Let them dry out a bit before watering. Junipers are very tolerant of less than average water at the roots. In fact they probably prefer it.