Getting rid of pachysandra overtaking a hill
I know you have heard this one before. My neighbor has pachysandra growing on the hill that has crossed into our property and is headed toward my irises, grasses, and ligularia that are thriving. It's a long stretch of property along the property line. I have read that it is best to dig it up going 4 inches deep, putting in some barrier and spraying to kill the roots. My concern is that weeds will take over once I have taken these steps. I am using vinca on the hill and it is filling in nicely in some areas but weeds exist in number also. Also is vinca an ok choice to allow for irises, some grasses, ligularia on top, some hellebores in shaded areas? The hill is mostly sun.
Baltimore County Maryland
Yes, you could put in edging material in to contain the spread of the Pachysandra to your property. You are correct that once Pachysandra is removed, you will need to fill in the space so weeds do not take over. Vinca is an invasive plant, so we do not recommend its use as a groundcover. (See the following article from the Maryland Invasive Species Council: http://mdinvasives.org/iotm/jan-2019/). Your other plants, irises, ligularia, etc., can grow up through the Vinca, but it is a problematic plant that spreads into natural areas -- you will have to keep it contained to your property.
You mention that you have a hilly area with mostly sun. See our webpage with recommended plants for sunny sloped areas. https://extension.umd.edu/hgic/topics/native-plants-sunny-slopes There are also several groundcover options for sun listed on this page. https://extension.umd.edu/hgic/topics/groundcover-list