The aggressive growth habit of mint (Mentha spp.) works well if you want to fill in bare spaces around a house foundation. You can plant relatively few plants, and they spread through stolons, or runners, to fill out the bare spaces quickly. The stolons can spread underground or even above ground, though, and invade other areas of the garden, so you must bury a barrier along the garden edges. Plant a barrier around the edges if you want a patch of several mint plants. Use a planter as a barrier to keep an individual mint plant among other plants around the house.
Cut sheet metal into strips about 17 inches wide, using a pair of tin snips. Wear heavy leather gloves to avoid slicing your hands with the razor-sharp metal. Use thin sheet metal that flexes easily, such as 26-gauge metal, especially if you have a curved flower bed. File the sharp edges with a flat file.
Call a utility locator service to mark the location of utility lines around your house. This is especially important when planting around foundations.
Lay garden hoses on the ground to form the outline of the new mint bed around the house. Spray chalk-based landscaping spray paint along the hoses. Mint needs a site in full sun to partial shade that receives about six hours of direct sunlight daily.
Remove all vegetation within the painted lines, and loosen the soil to a depth of about 12 inches in preparation for planting. Spread the soil smooth with the back side of a bow rake.
Plant the mint plants 1 to 2 feet apart in the planting bed. Plant each plant at the same depth it was in the transplant container so the top of the root ball is even with the surrounding soil.
Dig a 4-inch wide, 15-inch deep trench along the edges of the planting bed. Use a spade with flat sides to cut straight down into the soil.
Push the 17-inch wide sheet metal strips into the trench, leaving 2 inches protruding above the soil. Stand the metal straight up, and overlap the edges by about 6 inches so the mint roots can't spread through the joints.
Back-fill the trench with the native soil. Pack it tightly to hold the sheet metal upright.
Place a row of rocks or bricks along the edge, right beside the sheet metal to conceal the sharp metal edges.
Spread a 3- to 4-inch layer of bark chip mulch around the plants, but do not push the mulch directly against the plant stems.
Select a container that measures about 12 inches in diameter and at least 12 inches deep. Use a hard plastic container that won't crack easily, but that you can cut without breaking.
Cut the bottom off of the container to allow maximum drainage when you water the plants. Use a hacksaw or similar hand saw to cut through the planter.
Dig a hole in the planting bed that measures a few inches wider than the container diameter and 2 inches shallower than the container height.
Set the planter in the hole so the rim rests 2 inches above the surrounding soil. The rim of the container provides a vertical barrier to prevent the stolons from spreading across the top of the soil. Add or remove soil from the bottom of the hole to level the planter.
Fill the planter with a well-drained potting mix. The soil level in the planter should be equal to the garden soil level, so leave the 2 inches up to the top edge of the planter free of soil. Plant one mint plant in the planter so the top of the root ball is even with the potting soil level.