Skullcap
(Scutellaria lateriflora L.) 

botanical information

Scutellaria lateriflora L. is native to North America and can be found east of the Rocky Mountains in the temperate zones.  A member of the Lamiaceae family, skullcap is widely distributed in woods, moist thickets, marshes, and on the banks of streams.  It is an herbaceous perennial that grows to a mature height of twenty-four to thirty inches.  Leaves are ovate to ovate-lanceolate with serrated margins.  The blue flowers bloom from July to September with blossoms only on one side of the flower stalk.  The plant spreads through slender stolons and can fill in an area rather quickly.  It is the aerial part of the plant that is harvested and used for medicinal purposes.

medicinal uses

The Cherokee Indians used skullcap as part of a concoction given to women to promote menstruation.  It was also used for diarrhea and breast pain.  In the early 18th century in America, Skullcap was used in the treatment of rabies and was given the nickname “Mad Dog”, though it is unclear as to its success for treating rabies.  Today, it is used for digestive problems as well as a nervine and mild sedative for the treatment of anxiety, depression, and insomnia.

selecting a planting site

Although seed is commercially available, site selection is difficult.  Skullcap requires areas of constant moisture, such as moist thickets or marshlands, to grow.  It prefers a fertile soil, is hardy to zone four, and grows well in full sun or partial shade.  When growing in a hot, dry area, shade and moisture must be provided.  Once harvesting begins, fertilize with a high nitrogen compost.  

planting

Skullcap can be grown through direct seeding, transplanting, or dividing the roots.  Johnny’s Selected Seed Co., Winslow, Maine, recommends the following guidelines for starting seeds.  The preferred method is to start seeds indoors.  Skullcap seed requires a cold stratification period and light to germinate.  Sow seeds shallowly in flats with a prepared soil mix.  Moisten and refrigerate at 40-50⁰F for seven days.  Flats can also be placed outside where the seeds will be exposed to nighttime cold temperatures.  After the required stratification period, put flats in the greenhouse for germination.  Seeds should be started six to eight weeks before setting out in the field.  In late spring, transplant outside in well-prepared soil.  Space plants eight to twelve inches apart in rows one and one-half to three feet apart or in three-foot wide beds.  Once established, plants will spread quickly to fill the bed.  It is very important to keep the beds and rows weeded.

 Direct seeding can be done outside in spring.  In a well-prepared planting bed, shallowly sow one to two seeds per inch using the recommended row spacing.  When plants have several sets of true leaves, thin eight to twelve inches apart.  Do not allow the seeds to dry out and keep the planting beds free from weeds.  Once plants are established, root divisions can be made in spring or late fall.  This is the preferred method by Tim Blakley, Medicinal Herbs in the Garden, Field, and Marketplace.  Transplant divisions immediately at the recommended spacing and keep moist.     

insects and diseases

Diseases for skullcap, listed in Index of Plant Diseases in the United States, include the leaf spots, Cercospora scutellariae, Phyllosticta decidua, and Septoria scutellariae; stem rot, Botrytis cinerea; powdery mildews, Erysiphe galeopsidis, and Microsphaera sp.; and root rots, Phymatotrichum omnivorum and Rhizoctonia solani.

harvesting, cleaning, and drying

Once flowering begins the plant is cut with shears or a mower.  A light cutting the first year is possible, followed by two cuttings each consecutive year.  When harvesting skullcap, keep the freshly cut herb in the shade until harvesting is complete or take immediately to the drying area.  Do not allow the plant material to heat up.

 Blakley reports that skullcap can dry in three to five days but should be turned often.  The fresh herb is approximately eighty percent water.  A warm location with adequate airflow is needed for drying.  If a drying unit is not available, a large dehydrator, converted greenhouse, or converted rooms in a barn are areas that can be used for drying.  Dry at a 95-100⁰F, turning the herb often to allow for aeration and to prevent mold from developing.  Good airflow is essential.  For a quality product, full color of the herb must be retained after drying. In a more humid climate, the temperature may need to be increased.   Package the dried herb in woven poly bags that are light proof or in corrugated boxes, and store in a cool, dry, dark location.  Potential yield of 2000 pounds per acre of dried material is possible.

markets  

Buyers can be found worldwide for this botanical.  Both wild harvested and cultivated material is sold for the medicinal trade.  Small producers use established brokers to bring buyers and sellers together.  Some customers will deal directly with growers and harvesters, but most have specific harvest protocols. Many buyers require that the material be harvested at a certain time of the year or during a particular stage of bloom.

 Skullcap will grow in very select areas throughout North Carolina.  There are natural areas in the state that are suitable for cultivating high-quality skullcap.  This crop may be a viable alternative for some growers who have land less suited for other crops.

Felter, Harvey Wickes, and John Uri Lloyd. 1898. King’s American Dispensatory. Henriette Kress. Click here for the Web site.

Fernald, M. L. 1970. Gray’s Manual of Botany. D. Van Nostrand Company, New York, NY. 1632 pp.

 Foster, Steven, and James A. Duke. 1990. A Field Guide to Medicinal Plants Eastern and Central North America.  Houghton Mifflin Company, Boston Mass. 366 pp.

 Greenfield, Jackie, and Jeanine M. Davis. 2004. Medicinal herb production guides. North Carolina State University, Raleigh, NC.

 Jensen, Beth. 2004. Johnny’s Selected Seeds. Winslow, Maine. Personal communication.

Ministry of Agriculture, Food, & Fisheries. 2002. Certified organic versus non-organic budgets for American skullcap herb. 4 pp. Click here for the Web site.

Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. 1968. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, NC. 1183 pp.

 Sturdivant, Lee, and Tim Blakley. 1999. Medicinal Herbs in the Garden, Field, and Marketplace. San Juan Naturals. Friday Harbor, Washington. 323 pp.

 US Department of Agriculture, Crops Research Division Agricultural Research Service. 1960. Index of Plant Diseases in the United States, Agriculture Handbook No. 165. Washington, DC. 531pp.

The North Carolina Arboretum is grateful to Jackie Greenfield and Jeanine M. Davis for their contributions to this publication, including excerpts from their publication “Medicinal Herb Production Guides”. The Arboretum also wishes to thank Richard Rice for his artistic renditions of the herbs. The Superb Herbs Web site and the documents provided were made possible by a grant from the NC Department of Agriculture and Consumer Services, found on the Web at www.ncagr.com.