Juvenile foliage on itoigawa juniper


(Elena Thomsen) #1

Hi Jonas,

My name is Stefanos and I write to you from Athens-Greece.
I have some Itoigawa junipers that I wanted to thicken their trunk so I left the branches to grow a lot. When they had the right size I cut only three branches of every tree but in their place and also to other folliage, juvenile folliage came out. Could you please advise me what to do so I don’t have juvenile folliage in my Itoigawa junipers?

Thank you form your time.

Kind regards
Stefanos Papavasileiou


About the Questions category
(Jonas Dupuich) #2

There is no magic formula to avoiding juvenile growth on itoigawa junipers, but there are a few general guidelines. Juvenile growth can be triggered by:

  • making large cuts
  • strong feeding
  • strong watering

The only way to encourage mature foliage is to slow the tree down. Using less fertilizer and avoiding further stress (big cuts) can help the tree produce mature foliage. Note that this can take some time - giving the tree a break for the coming year will help.

Changing the soil can also play a role. Using a mix with no organic material offers greater control over available nutrients. Using a mix that retains better moisture means the tree can be watered less frequently. In practice, this can be accomplished by using more akadama, if it’s available, or other ingredients that retain moisture. Using smaller particles, up to a point, can also help.

While it’s tempting to cut off the new juvenile foliage, doing this can produce more juvenile growth so it’s best to leave it alone for the time being.

That’s great you’re producing junipers in Greece - I imagine they would do well there. Do let us know how it goes.


(stefanos Papavasileiou) #3

Hi Jonas!

Even though my reply comes very late I thank you very much for your reply! To tell the truth I never thought that you would have the time to reply so I didn’t visit you site for a long time. Also because of some personal problems I distanced from my bonsai. I have some very good bonsai materials(itoigawa junipers) which I bought them(very expensive) 10 years ago. As I long I had them in their small pots with acadama, everything was just fine. When I decided(3 years ago) to grow them free in big pots(so I can get thick trunks) with peat and big quantity of pumice, my problems started. As you guessed right, I gave them too much fertiliser and I cut some branches. I neglected them the past year because of my personal problems, I didn’t do any preventive spray for fungus and their tips from the Summer and then started to become all brown. They look very bad now so I don’t know what to do. Would it be a good idea to change the soil and then when they will seem better to air layer the branches so I can get rid of the juvenile folliage?

In Greece exist some bonsai enthusiast but in Athens were I live conditions are very hurch for bonsai, especially for white pines. It’s not only the big heat which is 35-45 celcious degrees in the Summer, we have also a big problem with spider mites and aphides which makes it a huge challenge to grow Bonsai in Athens.

Thank you for all the good work you do so we can get some Information and inspiration about our beloved hobby.

Kind regards
Stefanos


(Jonas Dupuich) #4

Ela Stefanos!

Thanks for the belated update. Based on what you’ve said, two things come to mind.

  1. If you are still trying to thicken the trunk, there’s no need to worry about juvenile growth at this point. Simply wire the branches that need bends and twists and let the tree grow.

  2. I’d worry more about the brown tips. If you do have a fungus issue, that’s the first thing to take care of. Repotting the tree into soil that doesn’t stay as wet and watching the watering carefully is a good start. You’d also need to spray and/or use systemic fungicides to keep it from coming back.

Can you upload a photo of the tree showing the brown tips?


(stefanos Papavasileiou) #5

Hi Jonas!

Thank you for your quick reply! I will try to send you some pictures today or tomorrow. I had in mind to change the soil end of March since Junipers wake up later than Pines. Do you think I should do it now?
Can you recomend a fungicde mix-blend for my junipers? I mean a combination of drugs that can cover many fungus diseases. I red in the Internet that exist some fungus that can’t be cure so I am a bit worry…

Kind regards
Stefanos


(Jonas Dupuich) #6

It’s hard to recommend a fungicide if we don’t know what the fungus is - or if fungus is the problem. It might be worth checking with a local nursery about what they use in your area.

There are several broad-spectrum fungicides that attack a number of fungi. Some are good for common juniper problems like phytopthera. Fungicides with mefenoxam fall into this category.

Using different fungicides over the course of several months is another approach, as is using both contact and systemic fungicides.

As for repotting, right before the junipers wake up is the best time.


(stefanos Papavasileiou) #7

Thank you for your reply. I will try to send you some pictures of 2 junipers so you can see if it fungus.


(Jonas Dupuich) #8

Doesn’t exactly look like fungus from the pic. Is just part of the tree affected? The foliage in the first photo looks good.


(stefanos Papavasileiou) #9

I have 10 junipers, 5 Shimpaku and 5 Itoigawa. The first picture is from a Shimpaku and all of the Shimpaku junipers have yellow tips and very little brown tips. In the past all of these tips you see in the picture were green. The juniper in the second picture is from an Itoigawa and the whole juniper is like this. In general all the Itoigawa have same symptoms and look more bad than the Shimpaku. What would be your proposal so I can get rid of these symptoms and cure my junipers…?

Thank you for once more for your time to write back!


(Jonas Dupuich) #10

Do the yellow tips look like this?

It looks like male flowers could be forming so those trees might be OK.

The brown tree doesn’t look good. It’s hard to guess, but it looks more like general stress or that it dried out than fungus.

Two common juniper fungus problems are phomopsis tip blight:
http://www.clemson.edu/extension/hgic/pests/plant_pests/shrubs/hgic2056.html

and phytophthora, which is a root rot issue:
http://www.extension.umn.edu/garden/diagnose/plant/evergreen/juniper/needlesyellow.html

Repotting the juniper and getting it into a soil mix with more air in it is the best thing for now in lieu of a good diagnosis.


(stefanos Papavasileiou) #11

No it’s not like the picture you sent me, I know what are male flowers.
In Spring my junipers started to have new green tips from the branches, these after a month started to have light green colour, then it became yellow and then it became kind of yellow-brown. I red in the past about these two fungus(Phomopsis blight and Kabatina twig blight) and I am afraid that my trees can have these kind of fungus but unfortunately can’t be cured. The ‘Brown tree’ can be also that it dried out some time in September since I left for one month and some one else was taking care of them. I don’t know…
Will do as you recomend and change soil beginning of March, but do you think I should do a preventive spray for fungus now?


(Jonas Dupuich) #12

If fungus is the problem, treating with a fungicide that specifically attacks the fungus you have is the way to go. In these cases, I’ll use both a contact fungicide and a systemic fungicide. I’ll continue to treat the trees through the growing season, using different fungicides at the intervals noted on the label.

Uptake is slower in winter so a contact spray as you suggest could make sense now.


(stefanos Papavasileiou) #13

Thank you very much for your help! I will do as you recomended and hope to have some good results.

When I repotted my first maple on the rock(4 years ago), found your article, ‘repotting a Trident maple’ and I red it probably 10 times to be sure of what I understood and do exactly as you wrote. I was very interested in what soil you use and the percentage of each component. Since then I visit vey often your site to educate my self.

Thank you for all the work you do so we can learn more about our passion!

Merry Christmas!


(stefanos Papavasileiou) #14

Hi Jonas!

This is Stefanos from Athens. Hope you had a nice vacation this Summer and your batteries are charged.

Wanted to give you an update from what I did to save my junipers. Repoted them in middle of March in a soil of Acadama, pumice and kiryu, then spray them 3 times with 2 intervals of one week with a MIX of fungicides. Unfortunately didn’t have any good results… After searching and reading a lot in the Internet I am thinking that my junipers have Phomopsis and also Kabatina twig blight. From what I red I must spray them in the Fall for Kabatina and in the Spring for Phomopsis(when I see new growth) and continue to spray as long as new growth continues. Also I must cut now, when the weather is still warm(we still have 30 degrees C), all the dead parts(folliage and small branches) of my Junipers.
Could you please tell me your opinion about this? Do you think I am in the right way?

Thank you for your time!

Kind regards
Stefanos


(Jonas Dupuich) #15

Is there an agriculture department at a local university that might be able to help with the diagnosis of the problem? If you can identify it with certainty, it will be relatively easy to follow-up with the appropriate fungicides.

I’d also be curious if fungus on junipers is a relatively common phenomenon where you live. If so, that might be a clue. Are there any nearby nurseries that can help?

I can’t identify the problem well from photos, but it’s clear the tree is stressed. I had similar damage on some itoigawa and simply watering less frequently coupled with good weather and mild fertilizer cleared up the problem.

When you repotted, did you leave some old soil in the middle of the rootball? If so, it might be worth repotting again this year or next to get rid of the last of the old soil. Even a little bad soil can cause surprising stress to junipers in some cases.

If the soil and watering is perfect, that leaves fungus as the next thing to address. The treatment you mentioned sounds relatively accurate, though the specifics are noted on the labels of the products and only apply when you know what problem you’re trying to solve. In general, when it’s warm and humid, fungus can spread rapidly.


(stefanos Papavasileiou) #16

Hi Jonas,

Thank you for your reply!
I didn’t leave any old soil when I repoted them, and I do the watering and fertilising as I used to all previous years. The nurseries here in Athens have knowlrdge and give you drugs that are about diseases that have the crops here, either fungus or insects. They don’t care about junipers or pines…
The agriculturist(she has a university degree in agriculture) who owns the nursery I go to buy my stuff, she asks my opinion about specific drugs and dideases she is dealing with, because she knows that I am reading a lot in the Internet. All the Information I get is from universities in the USA.
But unfortunately for me all researches from universities say that for Kabetina there is no cure…
I will try with some drugs that recomend for Phomopsis and I will let you know about the results.

Thank you for once more for all the effort you do and I wish you good strength!

Stefanos .


(stefanos Papavasileiou) #17

Hi Jonas!

Wanted to share with you my juniper progress with the fungus problem they had. When noticed new growth on them, started weekly spraying with 3 fungicides(as red in an article from the Connecticut agricaltural experiment station, how to treat kabatina and phomopsis blights), and have to continue it throughout all the growing season. They seem to do well but I have to wait a month more to be sure about the results. Then will send you photos how they look.
Do you have any experience in airl ayering pines? I have 2 scots pine and I am thinking to give it a try…

Thank you for all the aricles you post on the inetrnet. Can’t wait every week to read them!

Stefanos


Question about air-layering pines
(Jonas Dupuich) #18

Great news, thanks for the update! Ag websites are among the best resources for this kind of info - feel free to add a link to the page you found.

As for the air-layering question, I’ve replied here: Question about air-layering pines


(stefanos Papavasileiou) #19

Hi Jonas!
Thank you for your quickly reply! I am not that good with technology but think the link(for treating blights in Junipers) is this: http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/plant_pathology_and_ecology/juniper_tip_blights_09-26-12_r.pdf.

Thank you again!

Stefanos