Annoying weed - Ask Extension
I have this popping up all over my yard and do not know how to get rid of it.
Does anyone know what this is and how best to treat it?
Thank you.
Knowledgebase
Annoying weed #753728
Asked June 03, 2021, 11:31 AM EDT
I have this popping up all over my yard and do not know how to get rid of it.
Does anyone know what this is and how best to treat it?
Thank you.
Washington County Oregon
Expert Response
Hello,
I can't tell just from that picture, but perhaps with a bit more information I can figure it out. Could you give me an indication of how tall those plants are and how big the individual leaves are? Are the leaves directly across the stems from each other or do they alternate going up the stem? Have any flowered or shown signs that they're going to flower? (If so, a picture of a flower helps a lot.) Are they growing in wet areas and in shady or sunny spots? Also, if you can tell weather the stems are round or kind of square shaped if you feel them between your thumb and forefinger that would help.
Have you tried digging them up only to have them return or are you at the beginning of trying to get rid of them?
Thank you for your response. I will work on an answer to all of your questions.
Hi Larina:
I had to wait for the weeds to grow back before I could answer you. I have tried digging them up but it is difficult because they are so close to existing plants and the clay soil is hard to dig in. When I pull, I'm not getting the root. The root seems to grow laterally, running sideways and new weeds pop up all along that root trail.
The stems are round.
The tallest so far has been 27 inches and the largest leaf so far is 5 inches. I have no idea how tall it will get if I let it go.
They grow in the sun and in the shade, but seem to do better in the shade and where they get the most water from the sprinklers.
The leaves alternate going up the stem. So far it has not flowered.
I have attached photos of the weed growing by Hosta, under a pine tree and next to a Hotlip plant.
I used Google drive to send the pictures.
Hello,
Thank you for all of those great pictures. Unfortunately, I still can't identify the plant for you. I've gone through the entire Oregon list of Noxious weeds, and none of them seem to match. (I'll link to the list here in case you want to have a look yourself as sometimes leaves can look a little different at the seedling stage as opposed to the mature stage. It looks a little bit like a nightshade of some sort, but not enough that I can definitely point to that and those don't spread through underground runners though they do have a taproot that can be difficult to dig out.) There's also a possibility that it is a plant that is not normally considered to be a weed but can spread aggressively, like salal or spirea. (I don't think it is either of those, but they are shrubs that can spread fairly aggressively through roots.) One thing you might want to do since they seem to be popping up in a line is to follow it back to where you first noticed the problem plant and see if there is a larger shrub or tree that might be putting off new shoots or dropping seeds. It may be in a neighbor's yard or if you live near a green space it could be coming in from there.
Since I can't give you an identification at this time, I'll give you general advice for how to eradicate plants that spread through roots. This resource is from Washington State University. Control starts with what you have already been doing, which is to continue to cut off the plants, getting as much root as possible. If you compost, don't put any of that debris in the compost bin because some plants can resprout from small pieces of root. This is of course time consuming and tedious, but over time keeping the plant(s) from photosynthesizing will eventually starve the roots and they'll die. You can also try covering the troublesome areas with a thick barrier of mulch, plastic, landscape fabric, or even boards to keep the plants from getting sun. The problem with that is that it's popping up all around the beautiful plants you do want. So, you may want to consider using an herbicide. Normally we discourage people from using an herbicide on an unidentified plant. If you click on the above link from WSU and scroll down to the section on selecting a contact or translocated herbicide and the two sections below that, you'll find some information that may help you decide whether or not this is something you want to do. This is a broad-leaved plant that spreads through roots that keep resprouting so a systemic or translocated herbicide would potentially be more effective. It is possible to very carefully apply some systemic herbicides directly to the unwanted plant without touching nearby desirable plants, but you'll want to do it on a day with no wind. If you do choose to use a systemic herbicide, make sure to follow the label exactly.
I will continue to try to identify your weed, but I wanted to get back to you now while they are growing so aggressively. If you do find a larger shrub or plant you think they are coming from or if any of them ever do go to flower (which, of course, you want to avoid allowing them to do, but sometimes one gets missed) feel free to send me another picture.
Thank you for all of those great pictures. Unfortunately, I still can't identify the plant for you. I've gone through the entire Oregon list of Noxious weeds, and none of them seem to match. (I'll link to the list here in case you want to have a look yourself as sometimes leaves can look a little different at the seedling stage as opposed to the mature stage. It looks a little bit like a nightshade of some sort, but not enough that I can definitely point to that and those don't spread through underground runners though they do have a taproot that can be difficult to dig out.) There's also a possibility that it is a plant that is not normally considered to be a weed but can spread aggressively, like salal or spirea. (I don't think it is either of those, but they are shrubs that can spread fairly aggressively through roots.) One thing you might want to do since they seem to be popping up in a line is to follow it back to where you first noticed the problem plant and see if there is a larger shrub or tree that might be putting off new shoots or dropping seeds. It may be in a neighbor's yard or if you live near a green space it could be coming in from there.
Since I can't give you an identification at this time, I'll give you general advice for how to eradicate plants that spread through roots. This resource is from Washington State University. Control starts with what you have already been doing, which is to continue to cut off the plants, getting as much root as possible. If you compost, don't put any of that debris in the compost bin because some plants can resprout from small pieces of root. This is of course time consuming and tedious, but over time keeping the plant(s) from photosynthesizing will eventually starve the roots and they'll die. You can also try covering the troublesome areas with a thick barrier of mulch, plastic, landscape fabric, or even boards to keep the plants from getting sun. The problem with that is that it's popping up all around the beautiful plants you do want. So, you may want to consider using an herbicide. Normally we discourage people from using an herbicide on an unidentified plant. If you click on the above link from WSU and scroll down to the section on selecting a contact or translocated herbicide and the two sections below that, you'll find some information that may help you decide whether or not this is something you want to do. This is a broad-leaved plant that spreads through roots that keep resprouting so a systemic or translocated herbicide would potentially be more effective. It is possible to very carefully apply some systemic herbicides directly to the unwanted plant without touching nearby desirable plants, but you'll want to do it on a day with no wind. If you do choose to use a systemic herbicide, make sure to follow the label exactly.
I will continue to try to identify your weed, but I wanted to get back to you now while they are growing so aggressively. If you do find a larger shrub or plant you think they are coming from or if any of them ever do go to flower (which, of course, you want to avoid allowing them to do, but sometimes one gets missed) feel free to send me another picture.
Thank you very much for your time and advice. I really appreciate it and will check out the links you sent.
Would you please look at a couple of pictures for me again. After this I won't bother you again.
Is it possible that my so called "weed" is a tree? One got away from me and didn't get pulled. Below are the pictures. This is now almost 2 feet tall and when I used the LeafSnap app it identifies it as Populus nigra.
Is it possible that these are trees coming out all over my yard?
Thank you again for looking at this.
Thank you very much for your time and advice. I really appreciate it and will check out the links you sent.
Hello,
Yes it is likely those are trees. They do look like something from the Poplars or Cottonwoods. We certainly have plenty of cottonwood seeds floating around our area every spring, and some trees spread by suckers as well. Next time you are out on a walk look to see if you see larger trees that look similar to what you're finding in your yard.
Here are some resources if you want to try to identify further, but I'd recommend continuing to pull them up since they are close to your house. Perhaps next year if you see cottonwood fluff settling on your beds you can rake up as much as you can and then keep an eye out for seedlings when they are very small in early June.
https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/black-cottonwood
https://landscapeplants.oregonstate.edu/plants/populus-balsamifera
https://landscapeplants.oregonstate.edu/plants/populus-alba
https://leafyplace.com/poplar-trees/
https://www.uaex.edu/yard-garden/resource-library/plant-week/poplar-white-silver-1-13-12.aspx
https://leafyplace.com/cottonwood-trees-facts-types/
Yes it is likely those are trees. They do look like something from the Poplars or Cottonwoods. We certainly have plenty of cottonwood seeds floating around our area every spring, and some trees spread by suckers as well. Next time you are out on a walk look to see if you see larger trees that look similar to what you're finding in your yard.
Here are some resources if you want to try to identify further, but I'd recommend continuing to pull them up since they are close to your house. Perhaps next year if you see cottonwood fluff settling on your beds you can rake up as much as you can and then keep an eye out for seedlings when they are very small in early June.
https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/black-cottonwood
https://landscapeplants.oregonstate.edu/plants/populus-balsamifera
https://landscapeplants.oregonstate.edu/plants/populus-alba
https://leafyplace.com/poplar-trees/
https://www.uaex.edu/yard-garden/resource-library/plant-week/poplar-white-silver-1-13-12.aspx
https://leafyplace.com/cottonwood-trees-facts-types/
