Thanks for reaching out. I'd like to get a few more details to provide the best advice. Can you please take a few photos of the site? You can attach up to three photos as a reply to this message or email me at Brooke<personal data hidden> (message me at my email if you prefer to text photos to me and I'll send my number).

Are the weeds growing up through the weed fabric or in organic matter on top of the weed fabric? Or maybe a mix of both? Is it a certain type of weed or a mix? (Photos would be helpful).

Look forward to hearing back, Brooke

Hi, thanks for responding! I attached three photos: one of an area I've been working to keep clear, a second with some rocks pushed aside to see the fabric beneath (with my foot for scale :), and a third of an area more representative of the state most of it is in.

As you can hopefully see, there's a mix of weeds - I can't tell what most of them are but I can try to attach some photos of common ones in another reply maybe. There are definitely roots below the fabric, because we often tear or rip some when pulling them out. Now that you mention it though it does seem like some of the smaller ones may be growing above it.

Thanks!

Here are some photos of individual weeds from the area in the previous photo. Besides dandelions these seem to be the most common. A while back I looked through a weed guide I found somewhere online and also thought we might have "catchweed", "common groundsel", "creeping woodsorrel", and "prickly lettuce" though I could certainly be wrong. Quite the mess...

Thanks for your patience, I forwarded this question on to the OSU Extension Weed Management specialist and just received a reply.

Here is his advice, "It's going to be difficult to make a preemergence herbicide (Casaron) work in these conditions (rocks & landscape fabric). I would recommend treating with a glyphosate product now and as needed as new seedlings/growth emerge throughout the year."

His reply echos my own concerns about using Casaron in this situation. Casaron needs to be incorporated into the soil and is only effective against weed seeds that haven't germinated yet. It is ineffective against these existing weeds and because of the rocks and landscape fabric you won't be able to mix it in to the soil. The recommendation instead is to use an herbicide with the active ingredient of glyphosate. Glyphosate is a systemic herbicide so it moves from where you apply it to the leaves down in to the root system. It kills both annual and perennial weeds and is also non-selective, so it will manage both the grassy and broadleaf weeds in the area. You might find that with some targeted spraying this area will soon be much more manageable for future hand weed or spot application of herbicide. And a reminder: Always read the pesticide label for application and safety information.

If you have specific questions about using glyphosate or any other pesticide safely, I would highly recommend reaching out to the National Pesticide Information Center (NPIC). They answer questions by email and staff a hotline on weekday mornings. Contact info can be found in the top right corner of their website: http://npic.orst.edu

I hope this information helps you make an informed decision, please don't hesitate to reach out with any other questions.