Killing comfrey

Discussion in 'Planting, growing, nurturing Plants' started by IntensiveGardener, Oct 31, 2008.

  1. IntensiveGardener

    IntensiveGardener Junior Member

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    Hi all,
    I vagely remember some discussion some time ago about killing comfrey.
    I'v got a small bed which is covered in comfrey and is inside my hot house. Since i have a huge amount of comfrey growing very well outside the glass house i'd like to use the limited glasshouse space for something else.
    I'm pretty sure that attempting to digg it out is a waste of time, although maybe, if i used a sive to make sure all comfrey root was gone?
    I'd like to get rid of it as quickly as possible.
    any ideas?
    IG
     
  2. dylanz

    dylanz Junior Member

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    Re: Killing comfrey

    Hmm... was going to suggest just digging it out actually. It couldn't be worse than convulvulus ! I asked Bill about how to deal with rampant convuvulus once, and he claimed the only natural way to completely eradicate all the buried roots, etc, was by using pig.
     
  3. gardenlen

    gardenlen Group for banned users

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    Re: Killing comfrey

    g'day dylanze,

    i got rid of some in a garden once by pulling all the top off and not watering and then each day or as soon as a new sprout appeared pull it off, this starves them of food. wonder how you would go pull the top of of it and cover with thick newspaper and mulch for a couple of months??

    len
     
  4. Veggie Boy

    Veggie Boy Junior Member

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    Re: Killing comfrey

    I've never tried to kill any of my comfrey, but have managed to do it accidentaly a couple of times :oops:.

    I'd be inclined to solarise or just heavily mulch (as Len suggests). You could then plant on top of it (almost immediately) and the bromen down comfrey leaves will give the new plants a great start.
     
  5. pebble

    pebble Junior Member

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    Re: Killing comfrey

    Comfrey is very difficult to kill. Even more so if it's the purple/blue flowering one, as it's sterile so the only way it propogates is via the root. Digging will make it reproduce. I've had a below ground plant covered with a compost bin for several years and it still came back after a while.

    I'm interested in Len's experience. I'd guess lack of water would be the most important thing (would never work here as the ground doesn't get that dry). Lack of light for a period of time won't do it on its own unless you never dig there again (and even then it may still come back). Might be easier to move the hothouse ;)

    Can you use carpet and cardboard and then build a raised bed on top?
     
  6. Cares

    Cares Junior Member

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    Re: Killing comfrey

    I have the same problem, only it is in one of my garden beds.

    I am going to try digging as much out as I can, then lighting our incinerator and boiling up heaps of water
    and pouring it over the soil in the hope of totally cooking the rest of the roots.

    Cares :)
     
  7. pebble

    pebble Junior Member

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    Re: Killing comfrey

    Comfrey roots go down a long way.
     
  8. Veggie Boy

    Veggie Boy Junior Member

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    Re: Killing comfrey

    Jeez - you're all starting to get me a bit worried. I know comfrey is spread/propogated easilly by root cuttings, but I never thought too much about it ever becoming a problem for me (ie a weed).

    I'm just in the process of using cuttings from one of my larger plants (most of the others have died back (or altogether) during the drought) to make a border around my veggie patch (front and sides). I will therefore probably have 30 or so metres of comfrey. I hope I don't regret it in the long run. I don't think I will.
     
  9. gardenlen

    gardenlen Group for banned users

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    Re: Killing comfrey

    g'day v.b,

    not so sure i'd use as border, it may take over the bed, i found it is better grown away from vege' beds, around the drip line of fruit trees is a good spot. comfry does a very good job of going deep and taking nutrients from the soil and bringing it into their leaves.

    i tried digging it out of garden bed edge there is almost no way you can get all the roots, and any teeny little bit will grow.

    maybe if you grew it around the outside edge of the pathway instead of the bed?

    len
     
  10. Veggie Boy

    Veggie Boy Junior Member

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    Re: Killing comfrey

    G'day Len.

    I didn't explain it as well as I should have. The border is around the area that I use for my gardens and therefore is on the outside of the path (albeit dirt) that I use to walk around the beds. This means there is a gap between the comfrey and the gardens (though only 50cm or so) and this makes me feel fairly comfortable in growing it as I am. The idea is for it to keep the running grasses out of the garden area and of course to be chopped back and used as compost and foliar feed for the plants.
     
  11. IntensiveGardener

    IntensiveGardener Junior Member

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    Re: Killing comfrey

    Thanks for the replies everyone.
    I'm afraid the confrey is the purple flowered one (true russian comfrey) which only multiplies by root division :-(
    I'v tryed mulching heavily with newspaper then several feet thick of straw and the comfrey still came through!
    It worked well for fennel and sheep sorrel though :)
    I'm currently attempting to solerize it over the summer, then i might try what Len suggests if it comes back at all.
    Moving the hot house is out of the question as its hoops are concreted in.
    cheers,
    IG
     
  12. pebble

    pebble Junior Member

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    Re: Killing comfrey

    Let us know how you get on!

    Veggie Boy, it's only a problem if you want to remove it. In my experience and what I've been taught is that comfrey will only spread if you dig it. If you never dig it the patch won't get any bigger. That's the sterile comfrey at least, I don't know what other species do.
     
  13. DJ-Studd

    DJ-Studd Junior Member

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    Re: Killing comfrey

    That's exactly the reason why I have not yet planted it around my fruit trees but only as a border along the fenceline. I'm not sure that I'll be keeping the current layout of my orchard, so the last thing I want in 5 years is comfrey plants where they don't belong!
     
  14. dylanz

    dylanz Junior Member

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    Re: Killing comfrey

    Get a pig or two !!!
     
  15. ppp

    ppp Junior Member

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    Re: Killing comfrey

    I planted a couple of comfrey roots in my front garden a month ago, I've never had comfrey before.

    the gaden has pumpkins, spices - galangal, tumeric, cardamon, yacon, jerusalem artichokes, parsley, chinese keys, and a mango tree

    I am tempted to move the plants right down the far corner of my block away from any garden beds, to where the chooks always scratch around... am I wrong to do this say, this weekend to avoid the coming doom?
     
  16. pebble

    pebble Junior Member

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    Re: Killing comfrey

    You can try. Even if they grow back, it's still only a few plants. Is that a problem?

    You want to get all the root. How big were the plants when you put them in?
     
  17. IntensiveGardener

    IntensiveGardener Junior Member

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    Re: Killing comfrey

    while were on the subject. How far from the trunks of trees should comfrey be planted? I'v got rings of mulch around my fruit trees (which are curently growing broadbeans), which extend from about 50cms from the trunk to the edge of the drip line. Weeds keep comming up between the trunk of the tree and the mulch ring though and its hard to get at them without stepping on the mulched bit.
    Can i plant comfrey around the very base of the tree close to the trunk? or should i plant it in the mulched area and slash it down now and then to top up the mulch?
    Generally i love comfrey, its one of my favourite plants and i grow heaps of it. Even in a vegie bed the odd comfrey plant is fine, i just plant around them. The stuff in the hot house however has to go.
    IG
     
  18. Veggie Boy

    Veggie Boy Junior Member

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    Re: Killing comfrey

    I've gone ahead with my border. I only really had one decent comfrey plant left and was able to divide that enough to put in plants or roots for the full 20metre front of the patch - every 10 cm or so. Now that's good value :D . To make it even better - had great rain last night to water it all in :mrgreen:
     
  19. Mumchook

    Mumchook Junior Member

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    Re: Killing comfrey

    When doing my PDC the subject of unkillable comfrey came up, and the following was suggested, which I plan to try out too...

    Make a brew of comfrey leaves and water in a bucket, place a lid on and leave for a few weeks. When ready (not sure what constitutes "ready" but I'm leaving mine sit there for a while), pour it on the comfrey.

    I plan to cut the comfrey in the places it's unwanted and to carefully pour the mix on the cut stems, for hopefully maximum benefit.

    We had comfrey in a pot in the vegie garden, alongside a few herbs, however the thing went through the pot base unbeknowns to us. Trying to cut out the root was unsuccessful, and we even dug out a huuuge area of soil to get every piece of comfrey root possible, however that didn't work either as a few weeks after the soil was piled back and we were sitting back thinking we'd got it all out, up popped some more, in several more places nearby! They're all destined to get the comfrey brew... 8)

    Apart from that aspect, comfrey is great to have and I have it growing along a couple of fencelines, regularly feeding it to the chooks and the compost, with plans for it to hopefully help keep the kikuyu at bay... (is there a thread anywhere on killing kikuyu? :lol: )
     
  20. SueinWA

    SueinWA Junior Member

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    Re: Killing comfrey

    The only way I've known to kill it is to dry it out, and this can take all summer.

    If you can remove everything else from the greenhouse, do so, and close the doors and leave only the top vents open.

    If this isn't possible, chop it down, lay clear plastic (vented*) or heavy paving stones over it, and be religious about not watering in that area.

    * Vented because you're wanting to turn the area into a mini-greenhouse, heating that soil enough to dry it out, and you can't dry it out unless it's vented. Solarizing the soil is for another purpose, not this... exactly.

    Sue
     

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