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How to kill cottonwood seedling growth in grass and gardens? #871763

Asked June 05, 2024, 4:13 PM EDT

Hello! We just finished landscaping our new 2-acre homesite. Over the last 2-3 weeks, a large cottonwood tree (with which I've had no prior experience) has shed its seed-filled cotton all over our yard—on hardscape patios and driveways, artificial turf, recently hydroseeded grass, and mulch which covers the garden beds. We now have something growing EVERYWHERE in ouryard – on all of these surfaces (see below) -- and we assume it's the cottonwood seeds sprouting. I'm hoping you can help answer the following questions: Does this look like growth from the cottonwood? Is there a name for it? If not, any idea what it is? If it is from the cottonwood, how long will the trees continue to shed cotton? How do I get rid of this growth so it doesn't overtake my yard? The hydroseed company said it should naturally die out, but I'm worried about it choking out the new grass seedlings. Also, we need to fertilize the new hydroseeded areas twice this summer, and I'm afraid this will only spur the growth of this weed. I can't use a weed preventer on the hydroseed area until this fall when the grass roots are established. How do I eliminate this from the garden beds without killing all of the plants I just installed? Thank you for any insight or advice you can provide.

Columbia County Oregon

Expert Response

Teresa: I do believe that those are cottonwood seedlings! Do you think they could be vacuumed or lightly raked up without damaging your emerging grass? If so, I would do that right away. At least try it so if you want to hire a crew to do the raking, you can tell them how to do without damaging the grass seedings. I have not ever seen anything quite like this. 

There might be some herbicide options but they are more likely to cause damage to the grass at this stage of growth. 

Something else you need to know: cottonwoods send out shoots from their extensive root systems. These can also be a problem. There is a chemical option for that. But you need to work on this other concern first. 

Feel free to email me or respond to this AE question system if you have questions. <personal data hidden>

Chip Bubl OSU Extension Agent/Columbia  (retired) 
An Ask Extension Expert Replied June 06, 2024, 8:34 PM EDT

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