I have an increasing patch of periwinkle in my garden. Great ground cover, until it isn't... It's coming up everywhere.
Has anyone had any success in killing off periwinkle, without using pesticides? Every answer I can find says 'roundup' which, obviously, I don't want to use. However, it's choking out everything in its path, I need to deal with it.
My mother had people trespassing on her property to steal it. They were digging it up and selling it as starts for ground cover. Maybe somebody would be willing to come remove it for you in exchange for keeping it? Or you could see if there was a market for selling periwinkle starts in your area.
Alternatively, I have seen some types of grass take over and choke out periwinkle, however that may not be what you want to accomplish.
Maybe you could get into the herbal business, or supply this one item to an herbalist for them to use.
First, make sure your I'd is correct, to find the correct Latin name. Common names can be given to multiple plants.
Periwinkle roots are fairly shallow as it spreads. Maybe you can put a barrier around where you want the patch to stay and pull stray runners before they root. I don't think mulching will work cause it will just root in the mulch. Periwinkle prefers moist and not too hot, so mulch would be heaven for it...unless you mean like a couple feet of mulch. That might be enough to smother it. Maybe some cardboard or big leaves that mat together as a bottom layer. The patches I have in very hot spots with bare dirt around them don't really spread at all. The patches in cooler shady spots do.
I'm interested in this as well. The place where I'm living is coated in periwinkle, morning glories and english ivy (not to mention tons of little common buckthorn plants). There's a space in front of the house that has nothing but periwinkle growing and I'd much prefer to have some shade-tolerant plants & mushroom logs rather than the periwinkle monoculture.
I feel like a permie-minded approach might be the following, which I will also attempt this year:
Gauge interest for vinca minor starts with your local seed-saving society, freecycle group or kijiji/craigslist. Offer those starts for sale, or for free if people will come and remove them themselves. Transfer some to pots if you really want to keep some around in a more manageable form.
With whatever is leftover, have a periwinkle pulling party. It may be a small party thanks to the pandemic, but I find tuning into my favourite radio station (WFMU) makes any garden task go much quicker.
After disposing of all the periwinkle you pulled (everything I read says to just bag it and send to the landfill), lay down a bunch of cardboard, soil and/or a bunch of mulching materials to completely block out the light for any roots that were left below. You can keep adding mulch over time, and/or plant something on top that will continue to smother the area and make it extremely difficult for the periwinkle to pop up again, such as squash (if conditions are right), or some of Sepp's recommendations for heavy-feeding fast-growing plants like turnip and sunflower. But ultimately, I'm sure you could play with those plants and plant anything that you'd prefer instead, especially if you're putting a good chunk of soil over the layers of cardboard.