Dealing with the periwinkle problem

Hand pulling periwinkle (Photo by NCC)

Hand pulling periwinkle (Photo by NCC)

June 27, 2014 | by Mhairi McFarlane | 0 Comments

Jill and I did some follow up to some invasive species removal we did last year at Lathrop. Just a few fragments of the very invasive Periwinkle left! We picked them out by hand, leaving the native mayapple, trillium, Jack-in-the-pulpit and jewelweed to further expand and fill the few remaining gaps.

All to the wonderful sounds of woodthrush, eastern wood-pewee and Hooded Warblers singing — having recently returned to start nest-building at Lathrop. They should now have more insects to feed their chicks because of our invasive species removal work.

Click on the slideshow below for more detailed information about each picture.

  • No space for native plants. If large areas are supporting only one or two non native plants, plant biodiversity, or species richness, is low.
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  • Spraying the sea of periwinkle: NCC staff are licensed to use regulated herbicides. (Photo by NCC)
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  • We thought we were done with periwinkle, but then we found another large patch! This photo was taken March 2012, when there would ordinarily be very few or no green plants in southern Ontario, not a carpet like this!
    Click on the image to enlarge.
  • Almost exactly a year later: this is what most forest floors in southern Ontario should like in March – not green!
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  • And the same area again in May 2012, showing a riot of native mayapple. This particular patch also now supports trillium and wild geranium.
    Click on the image to enlarge.
  • This photo, also May 2012, from a slightly different angle, illustrates the importance of frequent and thorough follow-up monitoring after we have done some work such as removing an invasive plant. This small patch was missed by the spray.
    Click on the image to enlarge.
  • Small patches such as this can be carefully hand pulled, but it is vital to get all of the roots. This can be fairly straightforward when the soil is loose.
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  • ...and still some tiny fragments in May 2014, but we think we have got it all now!
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  • We will continue to monitor these areas once or twice per year. It can take some time for an ecosystem to recover from the disturbance the invasive plant caused, and the inevitable disturbance caused by removing it.
    Click on the image to enlarge.
  • Nothing but Japanese spurge 19 March 2012. This is another non-native plant that has escaped from a garden.
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  • Some mayapple persists, but the Japanese spurge forms a mat underneath.
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  • A healthy, southern Ontario forest floor in March.
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  • A sea of dead periwinkle with native plants growing happily. This photo shows just how targeted our spraying is. The few native plants that were just holding on in the face of the sea of periwinkle emerge unscathed, while the periwinkle withers at their “feet.”
    Click on the image to enlarge.
  • Wild geranium and white trillium happily growing where periwinkle was removed.
    Click on the image to enlarge.
  • ...But then we made the “mistake”? of visiting an area of the property we had not previously seen, and found a new sea of Periwinkle. Let the fun recommence! At least now we have a good system, which we know works, so we can better plan and budget our work.
    Click on the image to enlarge.
  • This is what we want more of – mayapple!
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About the Author

Mhairi McFarlane is NCC's conservation biologist for Southwestern Ontario.

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