[MAIPC] What Is It?

Atha, Daniel datha at nybg.org
Wed Jun 21 06:59:46 PDT 2017

To Margo Sterling via MAIPC,

I agree with the previous reply that the plant in the photos appears to be the non-native Persicaria longiseta.  It is indeed invasive and very common in the Mid-Atlantic region.  See the numerous observations from your region here: https://www.inaturalist.org/observations?place_id=52250&q=Low%20smartweed.  You can compare your plant to the images for confirmation.  And I hope you will post your images in the iNaturalist website to assist others.

Persicaria (Smartweeds) are characterized by simple, alternate leaves with a distinctive sheath (ocrea) at the base of the petiole.  Persicaria longiseta has the longest bristles on the ocrea (0.5-1 cm long) and by using this character the plant should not be confused for any of the native species (like Persicaria pensylvanica).  This is one of the few non-native species to invade woodlands and is therefore more troublesome.  Fortunately, as you say, it is easy to pull up.

Kind regards,


-:|:- -:|:- -:|:- -:|:- -:|:- -:|:-
Daniel Atha
Director of Conservation Outreach,
Center for Conservation Strategy
The New York Botanical Garden
2900 Southern Blvd., Bronx, NY 10458
Office: 718-817-8896 | Mobile 718-514-3922
Email: datha at nybg.org<mailto:datha at nybg.org>

From: MAIPC [mailto:maipc-bounces at lists.maipc.org] On Behalf Of Milo Pyne
Sent: Wednesday, June 21, 2017 9:27 AM
To: Patricia Greenberg <pgreenberg at reston.org<mailto:pgreenberg at reston.org>>; maipc at lists.maipc.org<mailto:maipc at lists.maipc.org>
Subject: Re: [MAIPC] What Is It?

the exotic small Polygonum (Persicaria) that we see most frequently in NC, LA, KY, TN, etc. is P. cespitosum/a var. longisetum/a (= P. longisetum/a)... and it does have long setae (long hairs from the sheath or ochrae).

I cannot discern that feature in these images; but that is the first one I would test this against.


From: MAIPC [mailto:maipc-bounces at lists.maipc.org] On Behalf Of Patricia Greenberg
Sent: Tuesday, June 20, 2017 3:07 PM
To: maipc at lists.maipc.org<mailto:maipc at lists.maipc.org>
Subject: [MAIPC] FW: What Is It?

We are working to figure out which invasive polygonum is in the photo below.

Any ideas?

Thank you in advance,

Patricia Pearl Greenberg
Environmental Resource Supervisor
Reston Association
12250 Sunset Hills Rd
Reston, VA 20190
(703) 435-6552
pgreenberg at reston.org<mailto:pgreenberg at reston.org>

From: Margo Sterling [mailto:jamasterling at gmail.com]
Sent: Tuesday, June 20, 2017 2:24 PM
To: Claudia Thompson-Deahl
Subject: What Is It?

Hello, Claudia.

My neighbor allerted me this latest invasion of our woods. This is a small green plant that has spread rapidly, and is shallow rooted. I have tried to use my 'plant identifier' app, but got totally confused. They eventually bear a small purplish flower on a spikey stem.

Would appreciated an identification, and some advice as to how to get rid of it. I am perfectly willing to pull them all up, but would appreciate a go ahead from you.
Thanks for your help.
Margo Sterling

Sent from my iPad
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