N-fix 7: Vetch

I was rather dissatisfied when finished with the Top ten ground covers for food forests series because I didn’t include an N-fix in the lineup of dynamic mulch. Vetch would be my first choice.

Crown vetch (Securigera/ Coronilla varia) is indeed the tyrannical ruler of the genus. It’s industrial grade ground cover, produces medium levels of nitrogen, stretches 3-4 feet tall, and eats as much as 60 ft of new territory in all directions via rhizome spread every year.


I’ve only seen this number in reports. I’m guessing the ground where these measurements were taken was the most fertile sandy loam on the face of the planet, or someone dropped a bag of fertilizer. I’ve never seen it spread more than four feet a year -if it spreads at all. many readers have likely seen this plant along highways where governments have seeded it. Erosion is a thing of the past once this perennial is established, so they have encouraged its use.

Once established though, they can start new colonies via seed. As a result, many governments have removed it from their official list of recommended plants.

It’s a little late. I have some patches appearing by the road at the edge of my food forest, and one of my clients has several healthy patches around their property. I have in fact installed this plant in one client’s system, because it really is quite useful, and easily controlled, if you know its habits.

The one system where I installed this for instance was a very high production food forest with long rows of shrubs and fruit trees running along swales (not my designs. I was brought onto the scene in the later stages). The owner wanted a system that could be managed by laborers simply weed-whacking the place every month or two. With this mentality, the owner had started by laying black woven plastic mulch under the plantings -despite my disapproval. It didn’t take more than two moths before weeds found their way through. He was aghast when I showed him. Finally open to my suggestions for a dynamic mulch, crown vetch was the perfect candidate.

As a dynamic mulch, it can exclude grass. Sometimes, if the grass is well established, the two may persist together. If well established, it’s nigh inpossible for weeds to get a foothold in the crown vetch’s domain.

It grows well seeded among daylilies, and most any plant that grows more than three or four feet -a food forest cover.

The crown vetch in my food forest has to creep across the upper grain patch before it can invade any of my plantings. This is one of the most poor spots in the food forest even the crown vetch can’t stomach crossing. I simply tax it for its nitrogen rich growth about the time it comes into bloom. Because it can be pulled so easily, I simply yank up whole armfuls to feed other parts of the food forest. As you can imagine, the patch is expanding at a snail’s pace.

My clients have done the same, and find their patches stay put.

Hairy vetch (Vicia villosa) and wood vetch (Vicia sylvatica) are both annuals, but have scarcely less ability to spread. Hairy vetch is used commonly used as a ground cover in vegetable gardens to be tilled in as a green manure. It and wood vetch are also medium level n-fixers. I have seen vilossa reach about four feet tall as it meanders around, such as below with wine-raspberry. Reports say it can reach as much as eight feet. So long as it doesn’t bloom and seed, there isn’t a problem.


I actually let the thing seed in my food forest because it grows right among weeds, grass, you name it -without complaint. I love it. When it blooms, I nab as many as I can for mulch, leaving the rest to seed. I really just wish I had more.

I came hit the jackpot the other day at my step-grandmother’s garden. She has the wood vetch, and a lot of it. I gathered a bunch of the pods as pictured below, which popped, flinging seeds every which way even as they sat in the bowl.


I planted them in a problematic part of the food forest to see how well they might compete with the grass. Perhaps they’ll clear the place for me in a similar way sunchokes can. in the bed I found it growing so happily, it was hardly three feet tall. I’ll just yank them up or cut them down before they make any very much seed.



  1. I’ve not come across vetch seeds here in Britain and not sure I need it, except in so far as it would be useful to have something which is N-fixing. Nice to see the photos, anyway – I’d always wondered what vetch looked like!

    Liked by 1 person

    1. I think a common name for the plant over in the UK is “tares.” Seedaholic has the common V. sativa species -which is essentially the same as the hairy and woods vetch. Plant World Seeds has some of the more rare perennial vetch-ish plants native to britain though. See here: https://www.plant-world-seeds.com/store/search_for_item?utf8=✓&query=Vetch
      Glad you found the post of interest! I’d love to hear how they work out for you if you do try them.


    2. Hi Helen, you can often find vetch growing in hedgerows or even car parks – I originally took mine from both these sources. If you would like some seeds I will be able to send you some as they are ripening their pods at the moment. Like Luke I find various vetches very useful for N fixing and they just get in amongst the other plants in a non disruptive way and look pretty too.


      1. Thank you for your kind offer, Anni. I’ve got various other seeds to use up or plants to ‘tame’ before I venture into the world of vetch, so I think it would be better not to take you up on your offer for now.

        Liked by 1 person

  2. I have quite a few different vetch in the tree field here and they seem to coexist quite happily with the grass. It would be interesting to see which would win if I gave the vetch a head start. It was something I was considering as ground cover in my fruit areas where creeping buttercup usualy seems to win. I’ll have to save some seed this year and move it around.

    Liked by 1 person

    1. That sounds fascinating and I would love to hear how it works for you in your situation. Around here, crown vetch will certainly take over if you let it bloom before cutting. The timing works so the vetch does indeed get a head start on the grass.


  3. Nice post – again! This particular vetch looks really nice and very useful, if as you say, handled well. I encourage as many vetch as will set seed to live amongst my other plants, they are so easy. I also have some birds food trefoil that arrived in the garden two years ago. That has grown more this year than last, probably getting itself established now. I took up lots of it and used it as a mulch round the nearby oca plants.


    1. Thanks! I’m so glad to hear you find similar experience with them. I do love birds foot trefoil. I first found it growing along the black top roads near my house. Still have not gotten it to grow in Mortal Tree, which is surprising considering where it usually loves to grow. Thanks for mentioning it though, as it is a rather vetch-ish plant. It was another ground cover I had the client I mentioned plant after we ripped up all the defunct black plastic cover.


  4. Very informative! Beautiful photos!

    Here in the Southeastern US, I put in Vicia villosa (hairy vetch) as an early spring cover for a broccoli bed, but with no plan beyond that. Well, it took over! Beautifully rampant. I didn’t want to tear it out and mess with the soil structure, so I would just come by every now and then and shear it with clippers. It went to seed, and the groundhogs got the broccoli.

    But, a fantastic idea – as a living mulch for a food forest. Bears experimentation in four months


    1. In my experience, it’s most proficient at coming back from the dropped seed. You may now have a semi-perennial planting of the stuff! Not a bad thing though if you properly manage it, as it seems you’ve already figured out. I have never tried a cover like vetch that would need to be cut back from among the annuals, and worked with short plants like mache in there. I like the idea though, for the fertility provided at least, and will have to try that in the annuals patch of Mortal Tree I’ll soon be reclaiming. Thanks.


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