About Sweet Flag: Opinions differ on the origins of Sweet Flag, also known as Calamus, meaning “reed”. Records show its early presence in India, and it later spread to Europe along trade routes. Because it also thrived in early North America and was a traditional part of Native American medicine, Sweet Flag may also be native to the United States. Medicinal uses included treatments for digestive problems and bronchial complaints, but the plant is no longer widely used internally because of FDA research that showed it to be a possible carcinogen. In medieval churches and palaces, its sweet, spicy fragrance made it a popular “strewing” herb for freshening the air. The essential oil is often included in perfumes and sachets, and also used in aromatherapy; calamus oil is one of the ingredients in an ancient recipe for anointing oil found in the Bible. The roots make a natural insect repellent, while the blade-like foliage has also been used as for thatching English cottages. Sweet Flag was a favorite of writers Henry David Thoreau and Walt Whitman; Whitman composed a series of “Calamus” poems, which he included in his famous poetry collection “Leaves of Grass.”
Sweet Flag Germination: To break its dormancy this seed needs stratification, a period of cold moisture; mix the seed with moist sand and store it in the refrigerator for 60 days before spring planting. To accomplish this naturally, simply plant the seed in late fall and wait until the spring for germination. Stratified seed can also be started indoors in late winter. Sow seed on the surface of a flat, pressing it down slightly but not burying the seed. Keep the soil very moist until germination, which should occur within 14 days. When plants reach 3-4” in height, transplant into pots; keep them in shallow water or water them often. After the last frost of spring, transplant 12-24” apart in full or partial sun and mucky, wet soil. This plant is semi aquatic and even tolerates standing water. The stratified seed can also be direct sown in early spring or late fall if the soil is given enough moisture. The plant’s rhizomes, when cut into 2-4” sections, can be planted 4-6” deep and 12-24” apart.
Growing Sweet Flag Seeds: Keep the soil very moist, even saturated; sweet flag does not tolerate drought. It grows well in shallow water, but avoid flooding seedlings or areas that have been direct seeded. Sweet flag also grows fairly well in normal soil, though its height may be slightly stunted. After two years, the plants can be divided for new plantings. Division should be done in spring to allow the plants to become established before cold weather. Sweet flag plants spread by rhizomes just below the surface, but are not invasive and can be moved without too much difficulty.
Harvesting Sweet Flag: Rhizomes can be harvested for new plantings in early spring before new growth, or in late autumn. Harvest when large and firm, usually after 2 – 3 years of growth.
Saving Sweet Flag Seeds: The white or cream colored bracht will turn brown as the seed matures in late summer or early fall. Harvest the brachts when they have ripened fully, and spread them out to dry away from direct sunlight. Rub them lightly to remove the seeds from the stems. Store the seed in a cool, dry place.
Detailed Sweet Flag Info: Origin: US Native Other Common Names: Sweet Rush, Calamus, Myrtle Grass, Calamus Root Duration: Perennial Bloom Time: Early Summer Height: 20-24 inches Spacing: 12-24 inches Light: Full Sun to Part Shade Soil Moisture: Wet USDA Zone: 4a-9b Seeds Per Oz: 6,800 Produces smooth, flat blades and occasional cylindrical white bracts 2-4” in height.