Moss imparts cool tranquility to shade gardens. Usually, you don't need to plant it; moss simply appears where growing conditions favor it: in deep or partial shade, on soil that is moist, acidic, and nutrient-depleted. You can fight moss—and many gardeners do, in a misguided battle to replace any natural groundcover with turfgrass—but it makes more sense to accept moss as a beautiful, low-maintenance gift from nature.
It turns out that moss grows well in containers, too. Inspired by luxuriant mosses that carpet nearby woodlands, designer Mark Kintzel of Allentown, Pennsylvania, planted a concrete urn with moss, then placed it in a shady location outdoors, where it thrived through spring, summer, and fall. The cushion moss (Leucobryum) Kintzel chose has a bubbly form and soft texture.
Gather the materials: a container with a drainage hole, growing medium, and moss. Pots made of porous terra-cotta or concrete will help keep the soil cool, although those made of other materials also work. Harvest moss from your backyard, or call friends until you find someone who has a patch of moss you can harvest from. Because moss has no roots, it peels easily from the ground and re-establishes just as effortlessly in its new home. It's not necessary to transfer any soil with the sheet of moss, and it doesn't matter if the moss tears into fragments.
Fill the container with the growing medium. Designer Mark Kintzel used compost; commercial potting mix (one without slow-release fertilizer) would work, too. If the medium is dry, moisten it slightly. Press firmly to compact it, and mound it into a dome.
Press small patches of moss onto the medium, arranging them to completely cover the surface.
Water as needed to keep the moss green and lush. Kintzel watered his moss urn about twice a week—more often during hot weather. Even if the moss dries out while you're on vacation, it will quickly revive once you resume watering.
Source for cushion moss:
Moss Acres, 866-438-6677 mossacres.com