Astragalus (Astragalus membranaceus) is a member of the bean and pea (or legume) family. Also called Chinese milk vetch, membranous milk vetch and huang-qi in Mandarin, astragalus is a perennial with small, ferny leaves that grow to 6 inches. It has a taproot, and after its yellow flowers fade it forms small seedpods. The root has been used medicinally for centuries; proponents believe that astragalus bolsters the body's immune system and that it benefits the spleen, kidneys, liver and circulatory system. If you have sandy soil and a sunny spot in your garden, you can grow astragalus.
Planting Astragalus Seeds
Scarify seeds before you plant them by scratching each seed with a nail file or nicking it with a knife--this will speed germination. Late winter is a good time to start astragalus seeds in most climate zones.
Deposit 2 gals. of non-salty sand into a garden bed that is about 2 feet wide by 6 feet long. It's better to start your seeds directly in the ground instead of planting them in pots or flats because transplanting them could damage the tender roots.
Test your soil to determine its pH. Astragalus prefers slightly alkaline soil, above 7.0. Dolomitic limestone and hydrated lime are recommended soil additives if you want to raise the pH.
Plant seeds 1/2-inch deep and about 4 inches apart. Germination should occur in three to 10 days. If your germination rate is good, you can thin out extra plants when they're about 4 inches tall. Leave 12 inches between plants.
Keep weeds down by mulching around the plants. If you use dried leaves, compost and other organic materials as mulch, they will break down and provide your plants with nutrients. Additional fertilizer should not be necessary.
Maintaining and Harvesting
Water your plants when the soil begins to dry out. Astragalus needs a moderate amount of water to do well, but does not thrive when it must grow in soil that is constantly wet.
Harvest roots in the fall when your plants are 4 years old or older. If you want to make a tincture, you can use the root fresh or store it in a warm, dark place until it is almost completely dry. Then cut the root into slices, either lengthwise or diagonally into chunks.
Protect older plants from rodents by setting traps around the growing area.
About this Author
Barbara Fahs lives on Hawaii island, where she has created Hi'iaka's Healing Herb Garden. Fahs wrote "Super Simple Guide to Creating Hawaiian Gardens" and has been a professional writer since 1984. She contributes to "Big Island Weekly," "Ke Ola" magazine and various websites. She earned her Bachelor of Arts at University of California, Santa Barbara and her Master of Arts from San Jose State University.