Vinca eradication - Ask Extension
Hello! I'm looking to get advice on how best to efficiently get rid of a very large, mounded area of vinca (likely minor?) on a part of the yard which...
Knowledgebase
Vinca eradication #865485
Asked April 22, 2024, 5:48 PM EDT
Hello! I'm looking to get advice on how best to efficiently get rid of a very large, mounded area of vinca (likely minor?) on a part of the yard which is shared with a neighbor. Fairly certain I could get my neighbor's buy-in, but wanted to get a better idea of what the process might look like before I spoke with them. Approximately 600sqft+area. It's shaded by a very large, beautiful cedar, established rhody, and medium-ish liquid ambar tree. Given its size, hand-pulling is a bit daunting, to say the least, as my back has seen better days. I've seen a couple OSU ext posts recommending mowing/trimming very low, covering w/ cardboard, and mulching with chips for some period of time. However, I think there's controversy about using cardboard + wood chips vs just chips? I asked a previous question of an ext expert about best practices for removing lawn and they recommended using just chips w/ no cardboard to encourage greater soil microbial biodiversity?. Can I get away with not using cardboard if a very thick layer of chips is used? How best to keep a thick layer of chips in place at the sloped edges? How long would I need to leave the chips in place before planting new plants? (looking to go with more native plants) Thank you!
Multnomah County Oregon
Expert Response
Removing unwanted vegetation like the vinca is usually a multiple year project. Persistence for years more to deal with regrowth is necessary with such an established and strong root system. It can, though, be accomplished.
Check out this WSU publication about wood chip mulch. The final page describes the steps. Treat your site like a restoration site and use 12 inches of mulch. It will slope off at the edges. The cardboard doesn’t increase the effectiveness of the mulch and causes other problems you can avoid by not using it.
A combination approach for such a tenacious plant would be to use systemic herbicide on break-through growth that you can’t pull out. Look for the label instructions for clip and squirt or painting for very targeted applications.
Regarding pulling: my experience is that by the second year, I can easily pull most weeds. The soil under the mulch is soft, and weed roots have moved up into the border where the mulch is.
Most advice I’ve read is that by the following year mulch can be pulled open in places for planting. Also, wood chips will need to be reapplied, but not as deeply as when you are smothering the vinca. You shouldn’t ever need to remove the chips. They will break down and incorporate into the soil more quickly than you might expect.
Here is an article about planting around established trees and shrubs. Be careful of the root systems.
Check out this WSU publication about wood chip mulch. The final page describes the steps. Treat your site like a restoration site and use 12 inches of mulch. It will slope off at the edges. The cardboard doesn’t increase the effectiveness of the mulch and causes other problems you can avoid by not using it.
A combination approach for such a tenacious plant would be to use systemic herbicide on break-through growth that you can’t pull out. Look for the label instructions for clip and squirt or painting for very targeted applications.
Regarding pulling: my experience is that by the second year, I can easily pull most weeds. The soil under the mulch is soft, and weed roots have moved up into the border where the mulch is.
Most advice I’ve read is that by the following year mulch can be pulled open in places for planting. Also, wood chips will need to be reapplied, but not as deeply as when you are smothering the vinca. You shouldn’t ever need to remove the chips. They will break down and incorporate into the soil more quickly than you might expect.
Here is an article about planting around established trees and shrubs. Be careful of the root systems.
Very helpful, thank you! So after reading the WSU publication, I could mow low in early spring (may by better to wait until next year) and cover w/ 12 inches of mulch and leave in place for a year+ before planting? And then stay on top of stragglers that pop up? Or would you still recommend pulling out as much root as possible initially?
Thank you!
Christine
I see no reason to pull it out listed in the resources that I have found. (I have pulled out vinca, and it's not very successful, as plants regrow from roots left behind.) The WSU publication says to kill perennial weeds if you can, and in your case that would be treating with systemic herbicide. I think the deep mulch will be enough, but take more time.
If you'd like to do it any time of year you can. I've seen people choose the early fall, as the winter rains will provide moisture to get the chips starting to work into the soil.
If you'd like to do it any time of year you can. I've seen people choose the early fall, as the winter rains will provide moisture to get the chips starting to work into the soil.
Thank you. One more question, if you will. Do you think it feasible to avoid using an herbicide?
Appreciate your time!
Christine
Yes, I do. It will take longer, but it will work in time. Persistence to manually remove all green growth, so the roots weaken and die is critical. You may find yourself needing to cut away green pieces every week or more at first.
