Firstly @owasco I am SO excited to have discovered #HiveGarden as a community! I Did not know it existed and came to read your post thanks to @Katharsisdrill writing his own 'garden' post in response to it.

This is what I LOVE about #Hive how it leads you down a path and you find more people and fun things to read.

I LOVE periwinkle as well, as having a big garden that needs 'neatness' here and there, it's a boon to shady tree lined areas, but I also know it can be a bugger to get rid of. I'd say mow it or use a strimmer on it and then find a good organic spray and just keep at it. Really, digging it would be the only One Season solution, but trim, spray in Spring and Autumn and maybe try to plant aggresive Annuals you love over it, like Petunias (if it's sunny) and let them block out the light. Have fun.

I'm currently making a new veg garden area at our place here on Cape Cod and am taking my old veg garden and converting it to more 'small orchard'. We've so many deer, rabbit, squirrel chipmunk that want ALL of our flowers and food, I have to fence it all.

Good luck and glad to have found #HiveGarden :)