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2017 Hard Frost & Invasive Species - What are others doing?

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A couple of weeks ago, the BCK CISMA area had a hard frost. The species impacted included a mix of inv. spp. and native spp. The following list is what has been observed so far. 

Invasive Spp. 

  • Knotweed spp. 
  • Amur cork tree
  • Black locust 
  • Oriental bittersweet
  • Tree of heaven

Native Spp.

  • Black walnut
  • Staghorn sumac
  • Mulberry

Are there any other regions that have had similar impacts? At this point, we are assessing the range of the frost impacts in our area and waiting to see if there are still treatments that can be done this year for knotweed. Some have suggested that for knotweed in particular, we may see lateral growth encouraged due to a top kill effect similar to mowing or a foliar spray of glyphosate. 

Any thoughts, insights, or experience with similar frost impact conditions?

J.knotweed - Frost Impacts 3.JPG

J.knotweed - Frost Impacts.JPG

Oriental bittersweet - Frost Impact.JPG

Amur cork tree - Frost Impact.JPG

Black locust - Frost Impact.JPG

Edited by Ryan Koziatek
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We had late frosts this year and last year that knocked the knotweed back as well.  For us, it mostly impacted the timing of our treatments by buying us another 2 weeks or so before treatment (since our spring treatments are timed based on how tall the plant is).  It could very well cause the plant to do more spreading for the reasons you described, though we didn't notice this reaction by the plants.

Treatments of woody species are generally done in midsummer or fall, so the frosts didn't affect our treatment of those plants as much.  Of course, we always celebrate an occasion that uses up some of the plants' energy for naught!

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