Plant herbs as ground covers, and the old adage, "time on your hands," becomes especially true.
Herbal ground covers translate to "thyme at your feet" when herbs carpet a sunny pathway, fill in the thin cracks between bricks along a shaded walkway, or grow between the crevices of patio stones. In his book, "Landscaping with Herbs," James Adams points out that "under or amidst larger plants and in open expanses, these low-growing forms will spread into one another to create dense covers, from knee-deep to thinner than the sole of a shoe."
Herbs are most often associated with culinary or fragrance gardens. As ground covers, they are fragrant, multifaceted, low-maintenance greenery. Some plants have been used to create medicine or dyes, and many are dried for potpourri or lasting floral arrangements. There are herbs for every location - whether sunny and dry or shady and moist.
Sweet woodruff (Asperula odorata) is an excellent choice for shady spots and damp areas. In late spring, the herb produces loose sprays of white flowers above a drift of narrow, whorled leaves.
Robin Siktberg, horticulturist at the Herb Society of America in Kirtland, Ohio, says to keep in mind that sweet woodruff's creeping roots spread rapidly. She notes, "It spreads; that is what it does best." Small clumps can be removed in the spring and relocated. Joseph Luebke, Horticulture Supervisor at the Washington National Cathedral, Washington, is also fond of sweet woodruff because he says, "it very rarely looks tired; it has a fresh, clean appearance."
Wintergreen, (Gaultheria procumbens) a low-growing, woody perennial with glossy leaves, grows well in partial shade. It prefers acidic soil and sports red, edible berries in the fall. A refreshing tea can be brewed from the berries. During the American Revolution, the colonists drank wintergreen tea as a replacement for the heavily taxed imported tea.
A rapid spreader and lover of shady, moist soil is the common violet (Viola odorata), a low-growing perennial herb. Its young, highly nutrient leaves can be added to salads. The wood violet likes damp spots and limy soil and bears spring flowers in shades of purple, violet, and occasionally pink or white.
Lamium, a low-growing shade- or sun-tolerant member of the mint family, is a perennial with white, pink, or yellow flowers in the spring that continues blooming through the fall. The variegated leaf varieties make lamium a pretty ground cover. Because it belongs to the mint family, lamium can become invasive and may appear in places where it is not welcome. Simply remove or relocate it, or share it with gardening friends.
In full sun, fragrant ground covers have the ability to release pleasing scents to those who brush up against the herbs. According to Harold Taylor, horticulturist and section gardener of the Idea Garden at Longwood Gardens in Pennsylvania, "Prostrate apple and peppermint-scented geraniums (Pelargonium odoratissimum and Pelargonium tomentosum) are wonderful, fragrant ground covers for a sunny area, and those passing close by the plants will catch the true scents."
The scented geraniums are tender perennials in climates where winters are cold. Bring them indoors to winter over if you garden in a cold climate, and treat them as houseplants. Once the danger of frost is over, they can be moved outdoors.
Harold also suggests mints. He finds that they will grow in poor soil in sun or partial shade and help combat soil erosion. The creeping varieties such as Corsican mint (Mentha requienii) and pennyroyal (Mentha pulegium) make a mat-forming carpet of miniature leaves and flowers.
Other mints, with scents of orange, pineapple, lemon, peppermint, spearmint, ginger, and grapefruit, grow much taller. If they are kept trimmed, however, they may work as ground covers.
Many people avoid planting mint because of its invasiveness, but, if controlled, it's a fragrant and pleasing ground cover.
For a sunny spot, the thymes are excellent ground covers. Their flat growing habit makes a blanket of tiny green foliage with a cluster of mini flowers. Creeping thyme or mother-of-thyme (Thymus serpyllum) bears lavender flowers and is a fine traditional ground cover. Creeping red-flowered thyme (Thymus praecox sub. arcticus) and gray-leafed woolly thyme (Thymus pseudolanuginosus) with rosy-pink blooms are also fine choices for planting in the cracks between paving stones, patio slabs, or bricks along a walkway. They can be walked upon occasionally without being harmed. The thymes also can transform a rocky hillside or sloping bank into an undulating green and dense-flowered carpet.
Where full sun reigns, also try some of these ground huggers: perennial chamomile (Chamaemelum nobile), creeping golden marjoram (Origanum vulgare 'Aureum'), creeping winter savory (Satureja montans 'procumbeus'), creeping germander (Teucrium chamaedrys 'prostratum') and prostrate rosemary (Rosmarinus officinalis 'Prostratus')
The flowers, though tiny, add to the charm of these low-growing creepers. Daisy-like heads appear on chamomile. The greenish-yellow foliage on golden marjoram lends an interesting contrast when it joins other ground covers. Savory has a sprinkling of tiny, white flowers. Germander bears purplish-pink flowers, and small blue flowers adorn rosemary.
All of these ground huggers have fragrance. Chamomile's leaves give off an apple scent, and creeping golden marjoram has a sweet, savory aroma. Creeping winter savory has a pungent warm smell. A spicy scent is emitted when the leaves of germander are rubbed, and rosemary sends out a pine fragrance from its leaves.
Washington National Cathedral's horticulture supervisor, Joseph Luebke, ranks sage (Salvia officinalis) - another sun-loving herb - as one of his favorites because of its colorful foliage. Golden sage (S. officinalis 'Aurea') and purple sage (S. officinalis 'Purpurea') grow to 18 inches. Both make vibrant border plants.
When planting herbs as ground covers, they should be thought of in the same manner as any other perennial. Consider form, texture, balance, and color as some of the design elements to incorporate. Like traditional perennial ground covers, they can be an important element in the landscape. They can provide transition from one boundary to another. With a definite foliage texture or color, they can highlight special plants.
Red-flowered thyme or the germander's magenta flowers impart an uplifting impact on a somber spot. On the opposite side, a significantly bright area can be toned down with the soft-shaded, gray lamb's ear (Stachys olympica) or gray-leafed woolly thyme.
Herbal ground covers are useful, fragrant, and beautiful.
(c) Copyright 2001. The Christian Science Monitor