Irish Moss nightmare

Japonicus

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I wish this was just a bad dream...this is my wife favourite bonsai and the only JWP I have. It's on BP roots.
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After an hour of tweezing ^ half a quadrant of soil, some nebari and mostly working on the lower trunk, one side.
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another hour and then some heading into 4 hours lapsed, it's evident I have to tread on thin ice and repot.
A couple rotten roots, but mostly the akadama had turned to a thick mud, like spent cat litter (exaggerated).
The thin ice part is the tree is rebounding from a weekend state, and the top half of the soil where a normal
repot would occur, is mud. The Irish moss holds moisture, and robs nutrients.
Manual removal is replaced with fresh growth, but! last year it did go to seed, so I'm hoping, fingers crossed
the moss roots in the following pictures wither and die. I have my doubts.

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So with the roots so fine I truly don't see a bare rooting even, fixing the problem, but nonetheless
I truly feel the health of the tree would be further jeopardized by holding off on repotting.
One of these days it'll fit in that bonsai pot...had to go with the oval mica for now.
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If the top portion of the soil were like the bottom, there'd be no qualms with waiting another year.

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After working the bottom, and a ton of Mycorrhizae that was much thicker than the pics could capture
(all the bottom soil was clumped together with the webbing like fungi)
I went ahead and jetted the top portion of soil, roots, washing as much as I felt comfortable removing.
As you can see, the jetting only revealed more moss roots the deeper I jetted.
Quite a mat of very fine delicate roots this crud is.

Blended some of the mycorrhizae with the new soil and potted it back up.
The roots being interlocked, I won't use round up if this comes back.
I killed an Aspen tree 30 feet away (and all soldiers connected) from another Aspen who's stump I drilled and poured round up in.
This "moss" is not a broad leaf weed, so I don't see trying a selective herbicide either.
I will try the vinegar again...but let's see if this sprouts from just the roots 1st. I bet dollars to donuts it does.
 

Japonicus

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"the top half of the soil where a normal repot would occur, is mud"
What I mean is the area I normally would work the roots, the top half of that is mud.
When the vigour returns in a few years, I will go a lot closer to a bare rooting
though I doubt I'll ever get quite as far as a true BR.
Try covering the soil with plastic???
Hello Hack! No I haven not. Now, I think the repot was avoiding root rot.
I need to be a bit more attentive when watering this year, and until I can get at the soil and roots
in a more effective way. Some of these crossed roots will never come out in my care.
It's an ugly nebari, but I think I got a pretty good deal on the tree when I got it.

So, that said, do you think covering the soil, wrapping the nebari, and trunk would be detrimental at this point?
I'm hoping the repot is successful and the health picks up a bit.
I had been in the wrong mode with this tree and didn't know it, and that sucked a bit of health from it.
I now know not to pinch candles, rather grow and cut, and also to remove the flowers or pollen cones.
I never removed them in the past. Had no idea it was a strength pool. Gotta focus on recovery.
 

Johnathan

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This may be a crazy question, but I'm under the impression fertilizer kills moss. Couldn't you just douse it with liquid miracle gro?
 

Shinjuku

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Brent at Evergreen Gardenworks advises to carefully spray the moss with vinegar. It’s worked well for me. Here’s what he wrote:

This question comes around every couple of years. Spray the Scotch moss,
Irish moss, Pearlwort, or whatever you want to call it, with household
vinegar straight from the bottle. Use one those common trigger spray
bottles and set the head to fine. One or two 'spritzes' will do the job.
You don't want the excess acid getting into the soil. Don't water until
after it is dry and apply it to a dry, not wet surface of the moss. Be very
careful not to get the vinegar on the foliage of your plant, it will kill
the leaves it touches.
The real problem of Pearlwort is the almost microscopic seeds that scatter
everywhere. The vinegar has no systemic or pre-emergent effect, so the seed
will continue to sprout. You must reapply the treatment to the new plants
BEFORE they flower and seed again, unless you want to do this forever. It
is possible to control Pearlwort, I have done it, but it takes eternal
vigilance.
 

Wires_Guy_wires

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In addition to Brents advice, I want to say that it's best not to spray vinegar during the heat of the day. Mornings are best; they allow the stuff to evaporate a little. Evenings are second place.
Some bonus addition: acetic acid seems to have an effect on plants. For some reason, and in combination with certain plant hormones, it's a huge drought stress reductor. But only in small quantities.
 

Japonicus

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Brent at Evergreen Gardenworks advises to carefully spray the moss with vinegar. It’s worked well for me. Here’s what he wrote:

This question comes around every couple of years. Spray the Scotch moss,
Irish moss, Pearlwort, or whatever you want to call it, with household
vinegar straight from the bottle. Use one those common trigger spray
bottles and set the head to fine. One or two 'spritzes' will do the job.
You don't want the excess acid getting into the soil. Don't water until
after it is dry and apply it to a dry, not wet surface of the moss. Be very
careful not to get the vinegar on the foliage of your plant, it will kill
the leaves it touches.
The real problem of Pearlwort is the almost microscopic seeds that scatter
everywhere. The vinegar has no systemic or pre-emergent effect, so the seed
will continue to sprout. You must reapply the treatment to the new plants
BEFORE they flower and seed again, unless you want to do this forever. It
is possible to control Pearlwort, I have done it, but it takes eternal
vigilance.
Thanks @Shinjuku I will try the vinegar again. It had gone to flower and seed before
so hoping the cycle ends soon. It’s bad enough having the weed, but calling your hand
at repotting when the tre needs to rest exacerbates the problem it is.

In addition to Brents advice, I want to say that it's best not to spray vinegar during the heat of the day. Mornings are best; they allow the stuff to evaporate a little. Evenings are second place.
Some bonus addition: acetic acid seems to have an effect on plants. For some reason, and in combination with certain plant hormones, it's a huge drought stress reductor. But only in small quantities.
Great thanks, I’ll give this a go should it return.
 

Paulpash

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Broken down Akadama encourages this stuff to grow. I never get it because I use moler, pumice and lava. Maybe address the cause to prevent the problem?
 

Dav4

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I had a JWP grafted on JBP years ago that was nearly smothered by Irish moss one year... the pot may have been a bit big for the tree, the soil was small grained and stayed too wet, and the moss made that worse- re-potting was definitely in order. The 2 best ways to deal with it is to keep your soil open and light so the moss can't get a foot hold and to pull any of it as soon as you see it. As you've found out, once you got a heavy crop going, it's very difficult to deal with. I will spray straight white vinegar directly on moss and weeds periodically through the year with no ill effects.
 

Forsoothe!

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When you say round up, do mean Round-Up the herbicide? You can't mean you use that around a tree in a pot? That would be very bad.

The best thing you can do with a sick tree is slip pot it into the ground in the best light for the species. Pots are the problem in the first place any nothing is better for roots than the natural, cooler open ground. The terrible weed Irish Moss (not a moss) needs to be dealt with secondarily by picking it off with a tweezers as often as necessary, probably for years.

Most Mosses are substrate-specific. Some like high pH, and some like low pH. Applying vinegar to a high pH may kill it, but a low pH Moss might love it. You don't know what you have unless you know exactly where yours came from, then only maybe. Some, or most Mosses don't like metals. Epson salts, iron, and copper are problematic depends upon variety of Moss.
 

PaulH

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I also use Roundup applies with a paintbrush. works great and has never harmed a tree. Roundup is only absorbed through active foliage and is inactivated by contact with soil.
 

Forsoothe!

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Roundup is only absorbed through active foliage and is inactivated by contact with soil.
Not my experience. My old man used to pose the question to me when I was on shaky ground: "What happens if you're right, and what happens if you're wrong?"
In this case particularly, the roots of Irish Moss don't damage the trees by choking out the tree, do they? What they do is embed themselves into the bark of the tree, quite possibly all the way into the cambium level, which if true would be effectively grafted into the vascular system of the tree.

What happens if you're right, what happens if you're wrong?
 

Hyn Patty

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I wish I knew which species you are actually talking about. Irish moss, Scotch moss, and 'pearlwort' all come up on internet searches as entirely different species of plants - none of which are actually moss. From your photos I am guessing it is Sagina subulata. I've never encountered this in my potted trees and I've never seen it growing in nature around where I have lived. It's confusing to call it a moss at all.
 
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coh

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I've heard of people using roundup, applied with a brush, to weeds in pots. They say it hasn't caused problems with the tree but I've never tried it.

Vinegar is pretty safe and will knock back most weeds (including what is typically referred to as irish moss) and mosses. With irish moss I find that it doesn't completely
kill it with only one application, the top/active growth will brown out but it will regrow from the roots. So multiple applications are necessary. That said, I don't know if
it can be completely eradicated this way as the roots seem to be pretty resilient. A combination of pulling and vinegar works pretty well for me.
 

rodeolthr

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Irish/Scottish moss (sagina subulate) is a flowering plant and NOT a true moss. It appears that you have both on your pine......the sagina growing in the substrate and actual moss growing in the root zone and up onto the bark. This is very common in my climate until the heat of summer arrives. I use a medium bristle toothbrush to remove the actual moss from bark and roots.
 

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