The Genus Scutellaria
Skullcaps
Family: Lamiaceae
There are 479 species of Scutellaria. The genus has a subcosmopolitan distribution, with species occurring nearly worldwide, mainly in temperate regions. The common name, skullcap alludes to the resemblance of the same structure to "miniature medieval helmets". Most Scutellaria are annual or perennial herbaceous plants (the species we tend to sell are all perennial). There are a total of 44 species of Scutellaria in North America. 4 species in Arizona, 9 species in California and 6 species in New Mexico.
Skullcaps are used in traditional medicine, such as in traditional Chinese medicine. The root of Scutellaria baicalensis – a common component of many preparations – is marketed in volumes that have led to the overexploitation of the wild plant. Its rarity has led to an increase in price, and encouraged the adulteration of the product with other species of Scutellaria.
In 1773, Scutellaria lateriflora became a common treatment in North America for the “hysteria” and “hydrophobia” caused by rabies. Today it is still a popular medicinal herb.
The generic name is derived from the Latin scutella, meaning "a small dish, tray or platter", or "little dish", referring to the shape of the calyx.
Scullcaps provide nectar for butterflies, hummingbirds, and other species. Many of them are larval host for the Verbena Bud Moth (Endothenia hebesana)
The species we tend to have:
Paper Bag Bush (Scutellaria mexicana)
Rounded shrubby perennial growing to about 3’ though often smaller. Purple and white flowers appear appear April through June followed by little paper bag-like fruits that may persist all the way into winter. Leaves are drought and cold deciduous. Full sun, moderate to low water with good drainage, hardy to about 15°F. From a variety of habitat types across their entire range; foothills and washes in creosote-bush communities, mostly deserts but reaching lower margins of the pinyon-juniper zones below 3000 ft. in western Arizona, southwest California, southern Nevada, and a small disjunct population in west Texas (Brewster County). Also found in Baja California and northern Mexico.
Mexican Skullcap (Scutellaria potosina)
Herbaceous perennial growing to about 2x2’. Blue to purple flowers April through August. Full to part sun, moderate water, hardy to probably about 15°F. Found in rocky areas, washes and sandy areas, 2,500 to 5,500 ft. in Arizona, New Mexico, and into northern Mexico.
Pink Skullcap (Scutellaria suffrutescens)
Perennial plant growing usually under a foot tall but spreading about 2, rarely 3’. Pink flowers spring through fall. Full to part sun, moderate water, hardy to 0°F. From limestone ledges in Tamaulipas, Mexico.
Starrfire Skullcap (Scutellaria sp.)
Perennial plant growing less than a foot high but spreading to about 2-3’. Red flowers spring through fall. Full to part sun, moderate water, hardy to 10°F. Found by Greg Starr in the Barranca de Tolontogo, Hildago, Mexico on a limestone roadcut. Likely a new species waiting to be described.
Dark Violet Skullcap (Scutellaria resinosa x suffrutescens)
Tidy plant, usually 6” tall, spreads to about 15”. Dark violet flowers appear in warm weather. Full to part sun, moderate water, hardy to well below 0°F. This is a human made hybrid and doesn’t occur in nature.
The Paper Bag Bush (Scutellaria mexicana) is the largest species in our region, growing up to 3' tall rarely a bit taller. Photo by R.J. Adams, iNaturalist
Floral detail of Scutellaria mexicana. Photo by Marianne Skov Jensen, iNaturalist
The Paper Bag Bush (Scutellaria mexicana) is a very unusual species--the fruits are inflated "bags". Photo by Marianne Skov Jensen, iNaturalist
Mexican Skullcap (Scutellaria potosina) is a short perennial usually found in riparian areas. Photo by Damon Tighe, iNaturalist
Flower detail of Mexican Skullcap (Scutellaria potosina), photo by Alexis López Hernández, iNaturalist
Pink Skullcap (Scutellaria suffrutescens) is a tidy plant growing about a foot tall, spreading about twice as wide. Photo by ndrés Ortega Chufani, iNaturalist
Scutellaria 'Starrfire' is an unnamed species found by Greg Starr which stays under a foot tall but spreads about twice as wide. Best grown in a container. Photo by Blooming Advantage.