HVX and Glyphosphate

roblksdMay 20, 2012

This is another subject that came up in Les's post on Garden center recycling of soil and composting. I was wondering if a couple people would volunteer to do an experiment and kill few hosta that are growing in the ground and see how long it takes for the roots and crown to decay to a point that they are gone. I think you would have to have at least 4 plants growing in similar soil and lighting conditions and dig them up after set periods of time and sift the the soil. Probably at 1 yr, 18 months, 2 years etc. Hvx is a potexvirus that is in a familiy that effects many different plants. There are other strains of Potexvirus that effect hosta also. Jon, I believe you wrote in a post that you have not had an HVX plant. If I am incorrect on this please say so.This is NOT an attack ! I am curious why you recommend this method when you have not tried it. I also would like help in determining a definition of what is considered dead. If HVX needs a living host then at what point is tissue no longer considered alive. Rob

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I removed an HVX infected Halcyon and left it and the soil I removed in a black garbage bag in the corner of my yard for one or two seasons. When I looked into the bag when I finally got around to throwing it out, there were still roots. I've also found roots from past hosta lingering in the soil when I go to move something. I think the roots can take a really long time to decay.

That said, I am not terribly worried about it anymore. Until they announce that the virus is transmitted by anything OTHER than sap to sap contact, it does not seem terribly difficult to avoid spreading the virus in your own garden. I now choose to plant all my new host a in sunken containers anyway. Eventually they will probably make it into the ground, once I decide where they should go. In the meantime, if one should show signs of HVX, removal woud be a breeze.

I also would not be scared if planting another hosta in the same spot where I removed an infected one. I'd just remove the soil and line the hole with newsprint. I might not put my absolute favorite one there, but again, sap to sap contact is easily avoided. I happened to have planted Brunnera where my infected Halcyon was. Those Brunnera, as I understand just about all Brunnera do, came with another garden joy- nematodes. It's always gonna be something.

    Bookmark   May 20, 2012 at 2:44PM
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A thought that has been rattling around in my head for a while.....

...I think some have mentioned using Roundup to kill a hosta and then dig after hosta are done blooming and supposedly less susceptible to HVX spread. I wonder what is point of Roundup vs just digging without Roundup - if done after flowering how is it different in controlling spread. If any tissue is left after digging with either method doesn't risk seem to be similar. Or possibly worse with Roundup -since it seems logical that it would be easier to dig up a plant with firm tissue than one that is partially rotted.

There, now maybe the rattling will stop...


    Bookmark   May 20, 2012 at 2:48PM
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coll_123, you said "I also would not be scared if planting another hosta in the same spot where I removed an infected one. I'd just remove the soil and line the hole with newsprint."

I have done that, I removed the full clump with dirt - layed out a double layer of newsprint added new dirt and then my new hosta. Looking thru pics if was late summer of 2009. I keep an eye on this hosta as my experiment, but not too worried about it.

HVX bothers me, but doesn't worry me - if that makes sense.


    Bookmark   May 20, 2012 at 2:59PM
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bernd ny zone5

Waiting until 2 years is a very long time.
I have 3 of 250 total hostas with HVX this year. I just sprayed 3 with Roundup, will wait until plants are dried up. Then I will dig out the two very small plants, put them and the immediate soil into garbage. Then I will scoop up another layer of soil and exchange that with good soil at the fence.

The larger plant I will also dig up after plant is dried up, but first see how roots (if any) are doing. I will then do with it as I did with an HVX plant last year, when I placed all roots and plant into garbage, removed all the soil, then exchanged that bad soil with good soil from the fence, plus new humus. That spot from last year was replanted then with Krossa Regal and which does not show any HVX now.

    Bookmark   May 20, 2012 at 3:26PM
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OK, so it sounds like some of you ARE immediately replanting hosta into the same spot where an HVX plant was removed. Has there been any testing done with the newspaper method, or is this just a common sense idea to help prevent contact with broken roots?

    Bookmark   May 20, 2012 at 3:53PM
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bernd ny zone5

I got everything out of that hole, there were no longer roots in. There were no other hostas very close with intermingled roots. You have to do something like 'archeology', dig a trench first around the plant with a smaller shovel. That hole naturally will be bigger than when you cut out a hosta. So far that plant is OK.

    Bookmark   May 20, 2012 at 4:27PM
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Steve Massachusetts Zone 5b

I have some Lancifolia that I can kill with Roundup to determine how long it takes for them to disintegrate. But I have a couple of questions.

1. Is the rationale for applying Roundup for the roots to completely disappear or is it so that the roots would wither and be easier to remove (i.e. less likely to come into contact with and spread sap to other plants).

2. Wouldn't it be better to do this experiment in pots rather than in the ground? In this way one could inspect the root system easier and find out what is happening to it.

3. Wouldn't we want to know what different concentrations of Roundup do? It could be applied in its concentrated form or in the form that comes premixed.


    Bookmark   May 20, 2012 at 4:55PM
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Christine - Right or wrong it made sense to me at the time and the risk was a duplicate Sun Power hosta. I dug wide getting the hosta, roots and dirt out and the hole was much bigger than the new hosta going in. Tossed all the old dirt and infected hosta in the garbage.


    Bookmark   May 20, 2012 at 5:31PM
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bernd ny zone5

Paul, thanks for that newspaper idea, I will use that then too. I hate to lose a very nice location for years by not planting there again. Bernd

    Bookmark   May 20, 2012 at 6:52PM
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Christine, for me it is common sense. Based on the information we have now, you have to have sap to sap contact. They used to recommend waiting a year to replant in the same spot. Then last year (I think) there was a study where they found traces of HVX in a spot long after the infected hosta was removed. What was not clarified, as far as I know, is if that meant there were traces of the old roots left behind (which I can easily believe, based on my own observations), or if there was HVX somehow floating around in particles in the soil, which is a different matter entirely.

Even if you stick a new hosta in a hole with remnants of roots from a plant you took out- what are the chances you will get that sap to sap contact. You'd have to have wounds on both sets of roots, rubbing against each other. Unlikely, I would think.

I did not replant a hosta in the spot where I took out Halcyon. The brunnera looked good there and I saw no need to change it. The other infected one I had was Wolverine, in one of my hypertufa pots. I'm sure I got rid of all the soil and spritzed some chlorox in there, but yeah, another hosta now resides there. I just don't buy into the theory that you have to treat the spot like it's radioactive to hosta after you remove a sick one.

    Bookmark   May 20, 2012 at 7:28PM
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Paul, when you said "two layers" of newspaper, you meant like two open sections? Not just two simple open double sheets?

I have lined a lot of spots for flower beds with a pile of newspapers, yea many more than one, like maybe 3 sections. I had a lot of old welding rod cans (we carried welders on our boats offshore) and I poked holes in them, and placed them on top of the newspaper. Then I began dumping my bags of garden soil around all this. The welding cans stuck up so I could easily water the new plants, and then it went right to the root area. If I go to planting hosta in the garden directly, I think such a reservoir would make sense again. Surely it would help reduce the nematode highway of wet petioles up to the wet leaves.

I think it becomes more possible for every one of us to have a plant with HVX. So it would also behoove us to have a contingency plan, every part of it in place. I'm glad that I tested my suspect hosta yesterday, because today my DH tipped over his tall ladder and it fell very close to the bed with those hosta. Had they tested positive, I'd be a basket case tonight. Even had I sprayed them with the RoundUp last night, they would still be able to transmit sap to nearby soil, right where I plan to locate a great portion of my baby hosta collection.

Roots are very tough things. I have several old hanging baskets which once had Boston fern in them, and those roots, though dead, are such a dense mass I cannot split them apart. We've also tried to kill the roots of big rhizomatous briars, and just the top dies. Same with the roots of the trash tree, the camphor. You have to dig out every tiny piece of the root because it just doesn't die willingly.

I think if I have a hole in the ground where HVX was present, I would wait at least two years to put another hosta near it. Say you wait six months, put a hosta in the old spot, and it tests in 6 months with HVX. There you have to do it all over again. Another two years. My thought would be to dig it all out, get rid of it, plant something else there with new soil, and avoid the spot for hosta. At least for two whole years.

I have a thought, which I have not heard used in this situation. How about killing it with heat applied to the top and thus burning the roots before any of them are severed? When we had some big big old azalea roots, stumps like trees, we put some charcoal around the base and had it burn slowly for a whole day. The plant never came back where we did that. But nearby, we even drilled holes in the stump and filled them with RoundUp, and the dang azalea grew back from the small roots not far from the main stump. If it were not against city ordinance to have an open fire, I'd charcoal burn the rest of the azalea stumps this way and be done with it. It seems to work with azaleas, maybe it would with hosta.

    Bookmark   May 20, 2012 at 7:43PM
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donrawson(Z 5)

The rate of decay would depend greatly upon soil temperature and the level of moisture as well as other factors. The process speeds up a lot when the soil is not cold. (That's why we put food in a refrigerator.) So any experiment should record the soil temperature and the amount of moisture.

I also suppose the soil type and the pH are significant factors, as well as the size and density of the root mass.

    Bookmark   May 20, 2012 at 9:08PM
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Jon 6a SE MA

"Jon, I believe you wrote in a post that you have not had an HVX plant. If I am incorrect on this please say so.This is NOT an attack ! I am curious why you recommend this method when you have not tried it. I also would like help in determining a definition of what is considered dead. If HVX needs a living host then at what point is tissue no longer considered alive. Rob"

I have not had any HVX in any of my hostas. I don't have a lot only about 75 or so and growing. I don't take it as an attack but in trying to protect my plants I have read the many postings on HVX and I have looked at the studies from several universities and in all the data available. That is my interest. I don't think that whether or not one has had any plants with HVX makes them any more or less expert.

Each study clearly states that HVX cannot survive outside living hosta tissue. Each study also clearly stated that there was no means of transfer of the virus unless the infected plant was cut or scraped and fluid escaped. Also it was necessary to cut or scape a healthy plant in order to infect the healthy plant.

When I saw recommendations to sterilize a shovel and dig up infected plants I saw several things wrong with this. First you will cut the diseased plant and introduce fluid. Second you may cut into healthy hostas and spead the virus. Third you may very well leave live tissue in the ground from roots that will remain as a source of contagion for over 2 years.

It makes ultimate sense to me to kill the infected plant before digging it up. Why glyphosate? Commonly available. We did have expert advice that normal concentrations of glyphosate would not do the job on thick leaved hostas. I would suggest then concentrate not diluted to kill the hosta. In my opinion it might take 2 applications, but I cannot imagine a hosta living through having all its leaves painted top and bottom with a concentrate. I would mix in a little Dawn as well as this will help wet te leaves and may even help absorb the glyphosate. It is an anti-virus in the case of HVX.

Many have given me a lot of "urban legends" about how the HVX virus may go dormant or how it can live outside of living tissue. 3 universities that have conducted experiments over the course of over 3 years say it doesn't happen. The claims that HVX can survive without live tissue or go dormant are old wives� tales. It is as simple as that. Some viruses can, HVX cannot and this is a proven fact. My system may not be proven, but these facts have been proven and re-proven.

Digging up an actively virulent hosta is playing Russian roulette. Killing it first makes ultimate sense. You don't have to have had an HVX infection to know this.

Paint the hosta top and bottom of each leaf with concentrated Roundup (Glyphosate) with a couple of shots of Dawn dishwashing detergent mixed in. Roundup says that their process is systemic and will kill weeds down to the roots in, at maximum, one month. Hostas may be tougher than the average weed so I recommend the concentrate and maybe repeat after a week. After it is shriveled up then it should be dead down to the roots and the virus as well. After a few months then it would seem to me there is no live tissue in the ground.

The only real question is, how do you most effectively kill a hosta. Now, many of you may have a lot of experience in this. Not having killed one, I am an amateur. I can't think of any method that kills to the root more effectively than glyphosate.

Have I done any experiments to prove this, no. All I know is that it makes ultimately more sense than taking a shovel and slicing into an HVX filled hosta. This is like a surgeon cutting into a festering infection. It makes absolutely no sense at all.

    Bookmark   May 20, 2012 at 9:43PM
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buckeye15(No OH)

Steve and don r have touched on a few of the difficulties of gathering any meaningful info from this "experiment". There are so many variables in this idea that would vary dramatically if you spread this around to different areas. Soil type, soil moisture, nutrient levels, pH, drainage, temperatures, etc.

And that is even before we start discussing concentrations of herbicide, which cultivars, etc. There is a reason most "studies" are done at the university level where they can control all the variables, so as to obtain meaningful data.

As a professional who as applied pesticides for over 30 years, I would never condone or encourage anyone to apply any herbicide (or other pesticide) at anything other than the label rate. The idea of applying a concentrated herbicide at full strength instead of following label dilution rates is absolutely abhorrent to me. Also I would be very concerned about using one of the formulations of Roundup TM with a brush killer like triclopyr mixed in. Some of those "brush killers" can do a great deal of harm to woody plants nearby and can persist in the soil, unlike glyphosate. They are very bad choices for landscape beds.

Having said all that, I encourage people to try this little experiment, and hopefully we can all gain some insight into how well it would (or would not) work.

    Bookmark   May 21, 2012 at 6:39AM
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Jon 6a SE MA

Paul asks "I wonder what is point of Roundup vs just digging without Roundup - if done after flowering how is it different in controlling spread."

The studies say transmission is less likely if done when flowering or in the Fall.

Relying on timing will reduce the risks, no doubt. Killing the tissue will eliminate the risk 100%, no doubt. Painting the hosta before any attempt at removal, no matter what time of the year along with good sterilization is simply the best bet of preventing the spread.

Treating with glyphosate is inexpensive, will greatly reduce and probably eliminate any chance of spread and it can be used with your suggested timing method. I see a sure lessening or eliminating of risk with no downside.

    Bookmark   May 21, 2012 at 7:05AM
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ken_adrian Adrian MI cold Z5

i know its heresey ...

but dont you people own any other plants besides hosta ???

when ready.. dig out hosta... move over anything but hosta ...

i dont understand the need to plant another hosta in the same hole ..

there are a number of reasons farmer rotate crop .. and one of them.. is to avoid an ongoing monoculture.. which eventually leads to decline ...

dig it .. and throw an astilbe in there. .and be done with it ..


    Bookmark   May 21, 2012 at 7:26AM
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Jon 6a SE MA

Buckeye says "As a professional who as applied pesticides for over 30 years, I would never condone or encourage anyone to apply any herbicide (or other pesticide) at anything other than the label rate."

Good point. I don't think there would be any restriction on applying glyphosate according to directions once a week for a few weeks, if hosta, by way of their thick leaves, do not readily absorb the chemical. The question is really how can hosta be effectively killed removing the living tissue necessary for HVX virus to live.

To another of Buckeye's questions as to surfactants. No manufacturer of glyphosate products recommends doing this according to an ISU study, but-

"all products containing glyphosate labels recommend the addition of ammonium sulfate (AMS). The role of AMS as an additive with glyphosate is considerably different than the function of the non-ionic surfactants or crop oil concentrates (COC) commonly used with postemergence herbicides. Whereas surfactants and COC�s are active primarily on the leaf surface and improve absorption of the herbicide into plants, AMS is primarily active within the spray tank.

The addition of AMS to the spray tank reduces the amount of glyphosate inactivated by antagonistic salts present in the water."


This specifically pertains to those with "Hard" water which would impede the effectiveness of glyphosates.

Does anyone have any experience with killing hostas purposely with glyphosates or any other "weed" killer? I think the jury is out as to whether hostas are resistant to glyphosates. I would ask anyone with an infected hosta to try painting it and within a month we should have at least some idea. If there are multiple infected hosta then try one, 2 spaced a week apart and 3 spaced a week apart and let us know the results. I think that no matter how tough hostas may be to penetrate, there would be none that could survive 3 paintings. If one could, I would really be surprised, but that is the reason for experimenting. Questioning everything is pure science.

Once again, I think, the real question is how can we effectively kill the tissue. There is no question that, once killed, there is no possible way to transmit HVX.

    Bookmark   May 21, 2012 at 7:36AM
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Ken, I have a small garden- probably about a hundred hosta and really not even enough room for all those to reach maturity. I have lots of other shade perennials, too, but the focus is on hosta- I think of the hosta as "specimens" and the other perennials as accents. I plant the accents in drifts or groups. Astilbe, for example, I don't like planted as a single plant. So unless I can squeeze three or more astilbe where I lost one infected hosta, I'm not gonna be happy with how that looks. Plus, in a small garden, some spots are more "primo" than others. To lose a choice hosta spot would suck, IMO, and I'm not willing to do that (when and if it happens to me again).

    Bookmark   May 21, 2012 at 9:17AM
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Jon 6a SE MA

It is truly ironic that the subject of how to effectively and completely kill hostas would be a big topic on a hosta forum.

My suggestion for a test would be to take known infected hostas (testing would be necessary). Take half the infected hostas and treat them with glyphosates to kill them.

In the live group dig out the hosta, purposely damaging the roots and leaving some root material in the pot and replant with tested HVX free hostas that have Their roots cut.

Repeat the procedure with the "killed" hostas.

Grow the hostas and watch for results and test for HVX in both batches.

This should give an indication of how effective glyphosate is in killing the tissue and stopping the spread of the virus. Of course repeating this thousands of times under strict conditions would be necessary to determine the time it takes and how effective various regimens would be.

There is one thing for sure. Killing as much tissue as possible lowers the HVX level. Killing all the tissue eliminates all the HVX. These are facts according to the information developed at, at least 3 universities at the cost of tens of thousands of dollars.

In my opinion it would take a comparable effort to be specific as to optimum doses and results for various types of hostas. My only point is that clear hard evidence is available from very reliable and multiple sources that HVX cannot live without live tissue and that it makes ultimate sense to try and kill the infected tissue in the most effective way possible. Saying it doesn't make any difference because you believe the virus lives in the soil without a host or that it can lay dormant for many years is just plain scientifically unsupported. Will it mutate and attain these abilities? As a mere mortal, I have no idea.

Killing an infected hosta in situ has no drawbacks that anyone has put forth.

Ken's advice is, of course, excellent.


    Bookmark   May 21, 2012 at 9:26AM
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Chris wrote in the post Hvx and Tools that HVX can remain viable on a shovel for up to 3 weeks and in the ground for up to two years. I am not sure where he is deriving this information but I assume it was proven somewhere. He does not say it will live two years after killing the plant with glyphosphate but mentions it is living longer on or in an organic environment.I am not sure if viable means it is living on another host or is in a dormant like state and is capable of reconnecting with a host. I think there are enough real life examples to at the very least show the possibility that sap to sap contact is not the only means of transmission. Some of these same studies say it is possible to pass the virus into pollen and seed though the odds would be small and is unproven. Still in theory possible. Jon I believe that if science proves that HVX is actually killed by glyphosate when it kills the host and/or that the virus after this treatment does not remain in the soil from decaying plant material then that would be a great thing. For me until proven by science it is also unsupported. For me the drawback is this is a subject that is at a very early stage in research and many studies are usually narrowly focused. I prefer being very open minded and cautious and would recommend whether you use glyphosate first or not to remove the entire plant preferably in the fall. Sterilize your tools multiple times in the process and excavate and dispose of the surrounding soil in bags. Test and quarantine plants in the surrounding area and do not replant in that spot. A sculpture there would be nice. Rob

    Bookmark   May 22, 2012 at 8:49AM
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Steve Massachusetts Zone 5b


I'm pretty sure that not all of the questions we have around HVX have yet been answered scientifically. In the AHS summary report dated June 2010, some of these unanswered questions are posed.

Root/soil contamination issues. We found that clean plants could be contaminated by soil and infected debris. We need to study what occurs and why.
The effectiveness of different cleaning solutions on tools exposed to HVX (important for field crop production)."

I don't know if anyone knows for sure yet if HVX is lying in a dormant state in the soil or if it is still active among microscopic plant parts that exist in the hole in which the infected Hosta was planted. If, in fact, it is dormant, then you are correct that glyphosate is superfluous. If it's still active in the microscopic plant parts, then killing the host before removing it might be efficacious. We just don't know yet.


    Bookmark   May 22, 2012 at 10:34AM
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Steve, Thanks for posting that. I think that makes the point I was trying to say in a much better way. Chris was taking information from Dr Lockhart in his information about the virus staying active for up to two years in the soil. Steve great vocabulary I had to look up effacacious. Rob

    Bookmark   May 22, 2012 at 11:16AM
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