A delicate, sweetly scented perennial at home in shady woodlands and meadows, sweet woodruff (Galium odoratum) produces clusters of tiny white, funnel-shaped blooms from late spring to midsummer. At maturity, the plant reaches a height of 8 to 10 inches. The bright green leaves smell like freshly mown grass when dried and are often used in sachets and potpourris. Sweet woodruff, which thrives in cool climates, grows in U.S. Department of Agriculture plant hardiness zones 5 through 8. Plant sweet woodruff in spring or autumn.
Prepare a planting spot in partial or full shade. Sweet woodruff tolerates a range of soil types with a pH between 4.3 and 8.3. However, the plant performs best in average, well-drained acidic soil with a pH around 5.0.
Spade the soil to a depth of at least 8 to 10 inches. Dig in 2 to 3 inches of organic material such as compost, manure or pine bark to improve soil structure and help maintain soil pH. In addition, dig in a general-purpose, 10-10-10 or 12-12-12 fertilizer at a rate of about 1 1/2 tablespoon per plant.
Remove the sweet woodruff from the nursery container. Dig a hole about twice the width of the plant's root ball, but no deeper than the height of the root ball. Place the plant in the hole with the surface of the root ball even with the surface of the soil. Planting too deep or too shallow stresses the plant and may cause the roots to rot.
Fill in around the roots with soil, then pat the soil gently around the roots.
Water the plant to a depth of about 6 inches, which is enough to saturate the soil around the root ball. Keep the soil moist for the first one to two weeks, watering deeply whenever the surface of the soil feels dry. Thereafter, continue to water regularly during hot weather.
Spread 1 to 2 inches of mulch around the plants to keep the roots cool and moist, and to slow growth of weeds. Use a natural mulch such as shredded bark or dry grass clippings.