How much periwinkle do I need to plant to cover an area 40' x 3'? Allowing for it to grow in some, but looking quite lush to start.
Certified GKH Gardening Expert
This will depend greatly on the size nursery plants you use.
Space the holes 4 to 5 feet apart for traditional ground cover planting, or as close as 6 yo 8 inches apart for faster coverage.
Make sure you plant the plants at the same level as the nursery pots.
Put a layer of mulch in between the plantings but keep it an inch away from the base of the plants to allow excess water to evaporate.
Here is a link with proper growing information.