Lawn weed - very invasive

Discussion in 'Plants: Identification' started by Jenny Victoria, Jun 13, 2020.

  1. Jenny Victoria

    Jenny Victoria Member

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    There is a small three-leafed lawn weed spreading throughout the lawn. It forms a thick mat, grows about 2 inches tall, creeping along the ground. the leaves are pale green. It has currently gone to seed and the little seeds grow in a cluster of 10 or more typically. Each little seed has a few spikes on top. It grows very prolifically in the sunny part of the lawn, but has not invaded the area under trees yet. It is destroying the lawn. The plant is in the process of dying at this time. Does anyone know what this weed is and how to eradicate it. The soil is not good--very sandy despite being amended. Photo is attached. I would really appreciate any help anyone can give on this.
     

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  2. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    It's a fabaceous plant of some kind, almost certainly a Trifolium or clover. They are likely improving the soil, as most (all?) of this group are nitrogen-fixing. Can you recall the colour of the flowers?
     
  3. Jenny Victoria

    Jenny Victoria Member

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    You are correct, but after posting the request for info. I discovered that it is Black Medic (Medicago lupulina). It is supposed to improve the soil, but there is little evidence of that. It has destroyed half of the lawn. The flowers are almost clover-like and yellow, about 1/8 inch in diameter. The only remedy I can find (without resorting to chemicals or removing all the soil and replacing it) is to aerate and try to improve the soil. Am trying to hand dig the stuff out, but it has very very long tap roots. If you have any ideas for removing it, apart from the above solutions I would truly appreciate them. Thank you for responding so quickly.
     
  4. Acerholic

    Acerholic Esteemed Contributor Forums Moderator VCBF Cherry Scout Maple Society

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    Hi, there is a YouTube video on controlling Black Medic. It is chemicals and I don't really agree with their use ,but everyone to their own.

    It's a member of the Clover family so has very long roots. IMO as a previous lawn obsessive, I would remove by hand and re sow.

    Or you can go down the route of letting your lawn return to nature with native wild flowers that grow in your area. It can be very pretty !!!

    D
     
  5. Ron B

    Ron B Paragon of Plants 10 Years

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    Flowering plants compete successfully with turf grasses in mown lawns where site conditions permit this to occur. To achieve and maintain a solid turf grass monoculture on a given plot the required cultural approach must be provided.
     
  6. Acerholic

    Acerholic Esteemed Contributor Forums Moderator VCBF Cherry Scout Maple Society

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    I think the thing to consider for @Jenny Victoria and many others is that the perfect conditions so rarely occur, especially if you move to a new house with a lawn already in situ.
    Being an ex golf pro, I have seen many greens completely replaced with a scientifically researched soil make up. Only to find a few years later perennial weeds have started to strongly establish. This is not a single golf course btw but 'many'.
    IMO private lawns do not have the perfect soil for the perfect lawn, but people do ther best under the conditions they are dealt and very very few can carry out an operation that golf courses often do.
    D
     
  7. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    I'm not convinced it is black medick. There are inflorescences / infructescences present in the photo of either hairy calyces or single-seeded hairy leguminous pods.

    Here is a close-up of black medick: Medicago lupulina|black medick|Fabaceae –
    Here's another of the inflorescence and developed fruit: https://www.uwgb.edu/biodiversity/herbarium/Vascular_plants/medlup_fruit01gf500.jpg
    In this set of images, the last one of the series shows the developing inflorescence: Medicago lupulina (black medick): Go Botany

    I've circled the parts of what of I'm looking at in the attached image.
     

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  8. Jenny Victoria

    Jenny Victoria Member

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    Daniel, Thank you for your response. The seed pods of my weed do not look like Medicao lupulina. They are in "round" clusters and the individual seeds have a spike on top (I got one stuck in my finger). The stems of the growing plant are red, whereas the dead (or dying) plant are also red, but much thicker. I am attaching 3 photos taken 3.15 p.m. today. IMG_1015 of the plant growing in the back lawn; IMG_1018 of the dead plants in the front lawn, and IMG_1022 of the dead plant plus root and seed clusters. Also in the last one are a couple of individual seeds on the right hand side as well as a sprig of the growing plant showing the flower head. Any help you can give in identifying this plant and/or advice as to how to eradicate it would be very very much appreciated. Thank you.
     

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  9. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    It keys out to Trifolium dubium in the Illustrated Flora of BC, or small hop-clover.

    See Clover Management Guidelines--UC IPM for management of annual clovers, including some non-herbicidal methods.
     
  10. Jenny Victoria

    Jenny Victoria Member

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    Daniel, Thank you for the very quick reply. Yes, you are correct. I have looked up the UC IPM Manual and it looks like it is hand weeding. As an ex-Master Gardener I really do not like using chemicals in the garden, apart from the fact that I have animals. We have approx. 300 square feet of this awful weed in the front and it is scattered throughout the lawn in the back. Again thank you for your help and also thank you to all the people who responded to my query.
     
    Last edited by a moderator: Jun 18, 2020
  11. Creatrix

    Creatrix New Member

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    This thread was very informative: this is the worst year I have seen for clovers in my lawn (although I am leaning towards seeding for a bee-friendly eco lawn over the next few years). A landscaper recommended I set my lawn mower up higher, letting the flowers grow tall, then dropping the blade low to remove the flower heads. My question is: will this break the seed cycle or do these prolific and tenacious guests propagate via roots? (Walking across the lawn is a bit of 'skip-shuffle' around all the bees at this point)
     
  12. Tom Hulse

    Tom Hulse Active Member 10 Years

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    There is one non-chemical method that is so often overlooked for these because it works very slowly (1.5-2 yrs to full eradication). Just mow tall. The best solution is to out-compete the weeds, not worry about how to kill them individually (otherwise they just keep coming back after you kill them). Keep reseeding every fall and spring with your same species of grass (probably mostly perennial rygrass) quickly transition your mower height to 3.5" then 4". Start right now today with an organic lawn fertilizer and keep it up regularly during the growing seasons. 1" of water per week. Use a very sharp mulching blade. Your grass needs to keep the nutrients from the cut blades, so do not bag and take it away. The common problems with mulching are overcome by the tall mowing height, deep roots, and organic fertilizer.

    Ron talked about 'the required cultural approach must be provided'. I think he meant chemicals, but really, this is the cultural approach these plants want. When you mow taller, the roots grow deeper (reaching down to a bigger pool of resources) and the ground is shaded, reducing evaporation; so they get much more water. Taller grass will out-compete these weeds for water, sunlight, and nutrients.

    4" may not sound like the short golf-course type lawn you desire, but honestly, once it's tall and thick and lush, you can't see the height. You just see a flat, beautiful green surface. Alternatively, once you knock out the weeds in a couple years you can go back a little shorter and just keep it thick by fertilizing regularly and always adding seed every spring and fall.
     
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  13. Ron B

    Ron B Paragon of Plants 10 Years

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    No I did not mean chemicals.
     
  14. Creatrix

    Creatrix New Member

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    OK so a naturalized wildflower lawn is looking more and more attractive. Just mow for some paths.
     

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