Irish Moss nightmare

[Japonicus]

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.

It looks identical to this http://mikobonsai.blogspot.com/2010/05/weeds-and-soil-compaction.html?m=1
that TN Jim linked in another thread on this tree last Jan. Referred to as a Scotch moss.
Yes it is confusing who ever called it "moss", but it is for sale on the WWW and the only way I have to ID it.
Usually grown between pavers/sidewalks...
Let's hope you never do encounter it...

 

[Japonicus]

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.

You must've missed the part where I actually described killing a tree 30 feet away from another tree
when their shared roots, (locked roots, interconnected roots, whatever you want to call it, they were connected)
shared the poison. The tree/stump I poisoned I used a 1" auger on the stump after cutting it down, and filled the holes with round up.
In less than a week, another tree, 30' away looked like it had been struck by lightening with the leaves turning brown
on one side, in a couple weeks the entire tree and hundreds of soldiers were dead.
Now I have an acer Japonicum maple and an Autumn Moon maple in my yard with no shade.
The Autumn Moon has been there 10 years from a grafted whip, and I am now moving towards lifting it.
In the OP I said I will not be using round up. This is why. It's not shaky ground what if... it's just not gonna happen.
Now if I had lots of money and a good source to replenish any failures of JWP bonsai, I might give it a go.

...In this case particularly, the roots of Irish Moss don't damage the trees by choking out the tree, do they?
...

Actually in a combined manner they do. Due to the moss inhibiting O2 I'm forced to repot.
If an animal were choked to death, it would be a lack of O2 mostly, right? The weed also robs nutrients.
Combined with akadama, (which of itself is a good thing that I've been replacing with 1/4" turface)
roots smothering the nebari and soil, soil on top remaining damp with the weed there, like moss can do
all combines to choke the life out of the tree.

I agree with your what if query your dad posed, but haven experienced death of full grown in ground trees
using this herbicide, it just shouldn't even be considered where the roots are attached to desirable roots.
You're correct.

 

[Vance Wood]

I absolutely detest that stuff. Some of my trees get it bad several times a year, and I just pick a day and get out tweezers.

That seems to be the only solution. I knew someone who used Roundup and claimed it did no damage to the tree. I have not seen or heard from him in years.

 

[Hyn Patty]

I was curious, thanks. I have encountered it in the nursery trade to sell it but hadn't ever found it to be a problem in the pots of trees. Makes sense though and I'll keep that vinegar trick in mind, if I ever do!

 

[PaulH]

That seems to be the only solution. I knew someone who used Roundup and claimed it did no damage to the tree. I have not seen or heard from him in years.

I've used gallons of Roundup in my life. Used as directed it only kills what you want it to kill. I do have chronic leukemia , though.....?

 

[Shibui]

So much confusion and problems caused by common names.
Over here we call that weed 'starweed'. It is a flowering plant. It propagates by exploding seed pods and by runners and is extremely invasive once it gets a foothold. I would definitely advise get rid of this if you ever see it.
As far as I know vinegar will not deter this weed. Vinegar works great with mosses but this is not a moss.
I have used roundup on this weed and on oxalis. Painted onto the leaves and never any problem with the tree in the pot.

You must've missed the part where I actually described killing a tree 30 feet away from another tree
when their shared roots, (locked roots, interconnected roots, whatever you want to call it, they were connected)
shared the poison.

This can and has occurred but you are talking about the same species - which can graft roots. This issue is 2 vastly different species which grafting of tissue would be so infitessimly remote to not even warrant worrying about. We cannot graft maples onto elm rootstock or elms onto pines. Weed roots do not penetrate the cambium even when they grow on the bark or trunk unless the plant is a parasite like mistletoe. I have used glyphosate to treat this weed in pots with trident and Japanese maples, Elms - Chinese and English, pines and a range of other species. Never had a tree die as a result despite using glyphosate like this for more than 15 years on hundreds of pots.
You are welcome to pick weeds out with tweezers but just don't use the excuse that glyphosate would kill the trees.

A nearby bonsai grower has discovered that personal insect repellent kills weeds. I can confirm they shrivel and die in a couple of hours of spraying but have not used it enough to guarantee long term safety for the trees. Certainly no short term issue here. The brand recommended was 'aerogard' but I tried another (pump spray) brand with a different active and it also killed the weeds so not sure if it is the active, carrier or propellant that does the weeding.

 

[Potawatomi13]

Great thanks, I’ll give this a go should it return.

Oh, it will. Again and again until last flower never seen again! After killing several trees of roundup have been battling it with hemostat. Must get head of plant or will regrow. After 3 years end of battle finally in sight. Difficult to believe this weed actually sells as groundcover! Should be against the law!

 

[JudyB]

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.

Dan R. does this as well.

 

[Japonicus]

So much confusion and problems caused by common names.
Over here we call that weed 'starweed'. It is a flowering plant. It propagates by exploding seed pods and by runners and is extremely invasive once it gets a foothold. I would definitely advise get rid of this if you ever see it.
As far as I know vinegar will not deter this weed. Vinegar works great with mosses but this is not a moss.
I have used roundup on this weed and on oxalis. Painted onto the leaves and never any problem with the tree in the pot.

This can and has occurred but you are talking about the same species - which can graft roots. This issue is 2 vastly different species which grafting of tissue would be so infitessimly remote to not even warrant worrying about. We cannot graft maples onto elm rootstock or elms onto pines. Weed roots do not penetrate the cambium even when they grow on the bark or trunk unless the plant is a parasite like mistletoe. I have used glyphosate to treat this weed in pots with trident and Japanese maples, Elms - Chinese and English, pines and a range of other species. Never had a tree die as a result despite using glyphosate like this for more than 15 years on hundreds of pots.
You are welcome to pick weeds out with tweezers but just don't use the excuse that glyphosate would kill the trees.

A nearby bonsai grower has discovered that personal insect repellent kills weeds. I can confirm they shrivel and die in a couple of hours of spraying but have not used it enough to guarantee long term safety for the trees. Certainly no short term issue here. The brand recommended was 'aerogard' but I tried another (pump spray) brand with a different active and it also killed the weeds so not sure if it is the active, carrier or propellant that does the weeding.

Yes I know it’s a weed, just calling it the name it has been tagged here.
I’m just saying it’s not a broad leaf weed that could be targeted by a selective herbicide.
Could be wrong but...

As far as the species roots, I am quite familiar with Pando in Utah.
Give it a quick read. Pretty amazing.

...It would be fool hardy to introduce any herbicide to a trees roots in a weakened state
most especially when the roots are the weak link in the chain to begin with.

With the roots of the weed attached to the roots of the tree, I will err on experience and caution.
Then you have the likes of the post right after yours by @Potawatomi13

I agree this is invasive. I agree and why I started the thread, if one sees this on a tree
prior to purchase, to really think before purchasing the tree.
If one encounters it post purchase, to be diligent to not allow it to flower
(I had to wear safety glasses last year to keep the seeds from getting in my eyes when pulled)
and be aggressive with removal at 1st sight. It is attractive after all...I was ignorant when I encountered it.
Never had heard of Aerogard.

Any way I will repost here with updates as warranted.

 

[Forsoothe!]

I have always prided myself on my plants being weed-free, or as close to that as possible. Probably due to my early experiences with things that looked cute, ~ when young. Black Medic, Liverwort and Scotch & Irish Moss all came to me in purchased plants, like everyone else I'd guess, and by the time you figure out that you've got the devils tools, everywhere, it takes years, and years, and years to rid the area of seedlings. I kill enough trees without help. I don't need Round-Up or anything else in my system. It does travel. Spraying a weed in a driveway crack a foot from the lawn needs to be done very carefully because a week later I can see the tell-tale witness where the crack in the driveway meets the lawn. It's not my imagination. I have a typical suburban lot with lots of beds and make it a point to never let anything go to seed. I pick them and get them into the trash while they're young. Vigilence is the only thing that is safe and effective. I violate the rule every other year and pay the piper over, and over, and over...

 

[Brian Van Fleet]

Dan R. does this as well.

Yeah, my experience with Round Up is that it only kills what I spray it on. My understanding is that Round Up simply removes the waxy coating that allows the plant to retain water, causing the plant to desiccate. I haven’t been brave enough to try it on the Irish moss or oxalis growing on my trees. I might try vinegar first.

 

[WNC Bonsai]

I like the idea of covering the soil surface with a sheet of black plastic. However be careful since the plastic will heat up the soil if it is in direct sunlight. With the plastic there is no issue with Roundup effects and whether the vinegar will do the job, etc. It simply cuts off the light to the plant, No light, no photoshnthesis, plant starves to death.

 

[WNC Bonsai]

Yeah, my experience with Round Up is that it only kills what I spray it on. My understanding is that Round Up simply removes the waxy coating that allows the plant to retain water, causing the plant to desiccate. I haven’t been brave enough to try it on the Irish moss or oxalis growing on my trees. I might try vinegar first.

Not comlpetely true. Rundup is absrobed into the leaves and translocated to actively growing tissues where it inhibits enzyme activity and protein synthesis killing them. The op and others that have suggested that interconencted root systems can be damaged reflect this reality. It is also why it only kills actively growing plants. You can theoretically spray it on dormant plants and tree bark without any problems.

 

[JoeR]

Yeah, my experience with Round Up is that it only kills what I spray it on. My understanding is that Round Up simply removes the waxy coating that allows the plant to retain water, causing the plant to desiccate. I haven’t been brave enough to try it on the Irish moss or oxalis growing on my trees. I might try vinegar first.

Well to take care of the oxalis is simple, just eat it!

 

[Brian Van Fleet]

Well to take care of the oxalis is simple, just eat it!

I have plenty, come make yourself a salad.

 

[Forsoothe!]

It's action is in the root system, and that's why it doesn't affect Moss. Moss doesn't have roots. I use it on trays of collected Moss, but you have to give it plenty of time before transplanting the Moss to a tree.

 

[Kirky]

What you have there is Procumbent Pearlwort. Not sure if you can get this try Amgrow Organix Weed Blitz, does the trick without killing the tree. Brown vinegar will work too but you have to keep on top of it, once seeds pop its a chore to remove as they disperse to other pots. So spraying before seeds mature is the only way to keep on top of it.

 

[JoeH]

As you can see the roots are locked, so no.
As I said, I killed a tree 30 feet away in my yard from the tree stump I put round up in.

not straight round up, 1 or 2 percent. It won't kill any woody material just green leaves/plants. I do 3 percent at work and it won't even phase Citrus or oak seedlings one bit unfortunately. I sprayed the base of my big Vitex with zero ill effects.

 

[penumbra]

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.

I agree with the paintbrush application and have used it many times. However, roundup does not only kill by absorption of active foliage. This was what they claimed in the 70's when it was introduced. It will kill a plant deader than a hammer if you put it directly on a bare cut. This is an excellent way to kill bamboo and tree stumps. It must be a very fresh cut but it works every time. I have used this method for 30 years.