Japanese Knotweed?

Mar 28, 2011 4 Replies

Hi there,



I have a Japanese knotweed problem in my area, but am alarmed to see a huge number of seedlings popping up in the garden. I'm not sure they are Japanese Knotweed though, in fact I'm leaning towards thinking theyre not from google searches - can anyone confirm either way?



Here are some of seedlings, one has its first set of proper leaves.



Thanks in advance!!


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hi Jimbo, Im sure that they are sycamore seedlings, my garden is also full of them. best wishes, Lannerman

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Yes, I also have them right now and loads of the little blighters are popping up. They are sycamore seedlings.

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As above, these do seem to be Sycamore.

If you are worried about Knotweed, it grows from the rhizome rather than seedling so if you had a patch very nearby and it was growing then you could be sure this was the problem. Thankfully in your case it's not so!

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When you're looking at a seedling and trying to figure out if it might be Japanese knotweed, compare it to the photo here:

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you see the little red line around the stem at each leaf, with the papery pair of bract-looking things sort of wrapping around the stem? Those are modified stipules, and the structure, called an ocrea and it's pretty diagnostic for the knotweed/buckwheat family, Polygonaceae. No ocrea, and you can forget about the possibility that you're dealing with P. cuspidatum. This family also typically has swollen nodes, so the stems tend to look like knobby knees.

Good weed site:

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on P. cuspidatum:
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