Cork bark Pinus thunbergii

[Cruiser]

This is the first jbp I’ve purchased. I couldn’t say no to that bark. It reminds me of pitch pines in the sand dunes of Cape Cod. Gnarly and weathered, like salty old sailors.

The cultivar is Nishiki tsukama. It’s 15 years old. It’s been in this plastic pot for 5 years. Aside from preexisting fertilizer balls in the soil, no additional nutrients have been given.

The substrate appears to be basic potting soil. It is coated in a white fuzz, which I hope is mycorrhizal. The roots look ok but are pot bound.

Judging from the candles, the tree does not seem vigorous. It doesn’t seem unhealthy either. I’m chocking it up to being positioned in partial shade and never getting fed, but maybe it’s something else.

I’ve done some homework but realize that there’s a lot to learn and have questions.

-Given that the tree is root bound, would it make sense to gently put it into a larger container at this time? (Not mess with the roots). Or should I give it some fertilizer and wait for a proper repot next year?

-Would it be okay to wire a new leader into place at this time (while the branches are still flexible).

-Should I use liquid fertilizer to catch up on growth this year or sprinkle on some organic-granular?

If anyone has additional advice or tips they’d like to share, I’m all ears.

 

[19Mateo83]

All I know is that is indeed mycorrhiza and that is a very interesting tree.

 

[Brian Van Fleet]

On potting: I wouldn’t repot or slip pot it now that candles are opening. If water pools up before it drains through, just aerate the soil with rebar or a dowel of some kind. Run it straight down to the bottom of the pot in 6-8 places. You can backfill it with pumice or just leave it open. Repot next spring. Also, avoid man-handling the trunk like that so the bark isn’t damaged. Lift it with a higher branch, wrapped carefully in a towel.

On vigor: it looks healthy, corkers just aren’t super fast growers. Some say they devote energy to bark production, but I don’t really know how to verify that. I don’t do summer candle cutting on corkers.

On feed: yes, feed it heavily. I feed my trees with organic cakes and weekly drenches with fish emulsion.

Best of luck with your nice looking tree. Haven’t heard of that cultivar before, will have to search for it.

 

[Adair M]

It’s best not to repot this year. Just put it back into the pot you got it in, and wait until the end of next winter to repot.

you can try and determine where the real roots are. Corkers are usually grafted onto regular JBP stock, and the caliper is wildly different where the cork starts and where the regular JBP stops on the trunk. See if you can feel real roots down in the soil at the base of the trunk.

cork JBP are naturally weak growers. They put their energy into making bark, not growing. They need lots of fertilizer. And you probably can’t decandle every year like a regular JBP. Maybe every second or third year.

Yours has some character, but beware: they’re really brittle, and you really can’t wire them. If you bought this tree thinking you’re going to learn “how to do JBP”, this is the wrong tree! Corkers need to be handled with kid gloves! I consider them a “novelty” tree. Something to have that’s “different”, but not necessarily a good bonsai. I stopped messing with corkers about 25 years ago.

I think @Brian Van Fleet might still have a few, and you might reach out to him for advice.

edited to add: Ha! I see BVF posted as I was typing! Well, you got the same advice from him.

 

[Brian Van Fleet]

Found this in a compilation I had been working on (lately neglecting) about corkers. @Brent used to have this description on his website, but it’s no longer there. FWIW:

 

[Scorpius]

I have multiple corkers, but I'm a newb with them. Only advice I can give if it is indeed potted in potting soil make sure to not overwater and to let it get somewhat dry between waterings. Wet feet for these guys means death. I would CAREFULLY drill some holes on the sides of that nursery pot to aid in gas exchange for the roots till you can repot next year. Good luck.

 

[Cruiser]

These are the types of responses I was hoping for. Thank you. It’s reassuring to hear the tree is healthy.

The plan then will be to aerate the soil a bit.
Apply a heavy amount of fertilizer through the growing season.
And leave the tree in a bright spot to grow.

How well can corkbarks recover from root damage or loss? There is another similar tree available for purchase. Same trunk size, but it only had half the amount of roots and did not have as much mycorrhizae. It looked like it had lost roots from overwatering.

 

[Brian Van Fleet]

How well can corkbarks recover from root damage or loss?

Just like they do with everything…slowly. If the new growth is otherwise healthy and you have decent horticultural skills, it may be worth trying.

 

[Cruiser]

Sprinkled 5-5-5 granular fertilizer onto soil surface. Eyeballed it, would say approximately 5 tablespoons.

Birds and critters have tried to get at this fertilizer in the past, so I added a layer of pumice on top of it. Like a cat covering it’s poo.
The pumice layer is about 3/4” deep. To provide additional coverage I topped it all off with some lawn moss..


The soil was wet when I brought the tree home and still is damp. To mitigate any risk of over watering i have not tested for drainage issues yet.

 

[Brian Van Fleet]

I would get rid of the moss.

 

[Adair M]

I agree with BVF about getting rid of the moss. That kind of moss likes to attach to the bark, and spread up the tree trunk. Then, it eats away at the bark! Very bad, since the primary reason to mess with a cork bark JBP is to have cool bark!

 

[Potawatomi13]

Pretty cool looking tree looks much like wild Yamadori. Amount of fertilizer seems somewhat extreme. Hope is not too much

 

[Cruiser]

Pretty cool looking tree looks much like wild Yamadori. Amount of fertilizer seems somewhat extreme. Hope is not too much

Thanks. I heard “apply a heavy amount” so on it went. I figured that organic fertilizer wouldn't be harmful if too much was applied... I could always remove some. It’s sitting on the surface just below the pumice.
Looking the tree over I noticed some banding and yellowing of the needles. I understand that nutrient deficient or over watered pines will exhibit theses symptoms but I’m concerned it could be needle cast..

 

[Cruiser]

Some of the fascicles have one green and one brown needle. There’s various spotting and banding. Some of the younger needles are just falling off.
The dominant leader seems ok.
My gut is telling me needlecast. Could I please get a second opinion from someone with more experience?

 

[Brian Van Fleet]

Needle cast, use Mancozeb.

 

[Cruiser]

Needle cast, use Mancozeb.

Ordered.

Is it superior to daconil and/or copper fungicides in this case? If so why?
I have daconil and copper fungicide on hand. Is there any benefit to using a combination of the 3?

 

[Brian Van Fleet]

Ordered.

Is it superior to daconil and/or copper fungicides in this case? If so why?
I have daconil and copper fungicide on hand. Is there any benefit to using a combination of the 3?

Mancozeb works better.

 

[Cruiser]

Picked up two more pines. Same age as the other. From the late Dave Dewire.

One has fewer roots than the other two and no visible micorrizhae.

 

[Cruiser]

The tree with a reduced root ball needed more substrate to be secured in its pot.
It had a bit of loose soil in the bottom of the pot to which I mixed in pumice, 1 tbsp fertilizer, and some small wads of mycorrhizae taken from the root mass of the other pine.

1 tbsp of granular 5-5-5 dr earth fertilizer was given to the other new corker with good roots. Topped it with pumice to keep critters away. I found an id tag in the bottom of the pot that says “nana koyosho” jbp. This tree looks exactly like the other labeled “nishiki Tsukasa”. Perhaps the trees were mislabeled at some point..


Removed a bit of the fertilizer from the first tree from my older posts. I had sprinkled 4-5 tbsp onto the soil surface. I reduced it to 1-2 tbsp.

 

[Cruiser]

Mancozeb arrived today.
The recommended dilution is 2-5 tsp/gallon of water.
I’m leaning towards 2 tsp/gallon since the pines are not growing vigorously and one has a root system that is lacking. Does this dilution seem appropriate for my situation?

A plastic sheet will be laid on soil surfaces to prevent dripping into roots. Proper PPE will be worn.

I am also wondering if it is worthwhile to spray mancozeb on vigorous pines with only minor amounts of needlecast?