Most gardeners would probably not think of Skullcaps (Scutellaria) at the top of their list of the most garden-worthy members of the mint family. Many of the species native to the East Coast are rather unremarkable – beautiful in their own right but perhaps not shining stars of the perennial border. Three outstanding species in the garden have been completely overlooked by most of the horticultural community. All three are endemic (found only) to the Deep South, superbly adapted to our gardens, and all relatively uncommon. Scutellaria have the unfortunate common name of skullcap which doesn’t aid in their marketability when compared to the more inviting names of many other popular landscape plants. The name skullcap comes from the unique shape of the calyx (sepals). The sepals are fused to form what looks like a small dish or cup which is the meaning of the scientific name, but also reminiscent of a skullcap (hat). The sepals are persistent long after the blue to purplish tubular flowers fade and in some species can be fairly attractive and the inflorescences can be used dried for arrangements.
Like most members of the mint family, skullcaps are attractive to pollinators and often are highly attractive to smaller bees, syrphid flies, and butterflies. Ours attract small skippers in good numbers.
Scutellaria altamaha (Altamaha Skullcap) This remarkable skullcap is native to only a few counties in Georgia and South Carolina where it can be found growing in deep sandy or rocky soils that are often dry in deciduous woodlands and forest margins. Though even native plant enthusiasts are often unaware of this species, it deserves much more attention and inclusion in our Southern gardens. Altamaha Skullcap produces 1.5-2’ tall stems branching upwards and is tightly clumping, often forming a mound of attractive, tidy foliage that is topped in June and July with racemes of vibrant blue flowers. It is similar to both Mellichamp’s Skullcap and Ocmulgee Skullcap but distinguished by having stipitate (stalked) glandular hairs at the 2nd internode below the lowest branch of the inflorescence. Because of its tolerance of droughty soils, it is well-adapted to growing in gardens with limited irrigation. Given regular garden conditions with well-drained soil and ample fertility and moisture, it forms a much more attractive and structured plant than can be observed in the wild. (Hardiness Zone 7a-10b)
Scutellaria mellichampii (Mellichamp’s Skullcap) Joseph Hinson Mellichamp (1829-1903) was a prolific botanical explorer and collector from Bluffton, South Carolina in Beaufort County. He corresponded and sent specimens to all of the biggest names in botany including Asa Gray at Harvard. He discovered many plants that were previously unknown in South Carolina and some that have not been found there since. Ken Wurdack investigated his letters in an attempt to rediscover some of his long-lost collections such as Needle Palm – which was relocated. He shared some of these letters with me while Richard Porcher and I were surveying shell middens. The letters concerning the freed man Robinson Curusoe, who lived on an island in the marsh near Bluffton, led us to Mellichamp’s collection sites for Bluff Oak and one of the sites for Mellichamp’s Skullcap. Well, now that I’m done with the history lesson, we should talk about the amazing South Carolina and Georgia endemic skullcap that bears his name. This species is found in shell hash and rich forests over limestone in a very small area of the two states. Our plants are from a Bluffton population selected and named by Daniel Payne of Lady’s Island. It forms a 2’ tall clump in sun or part shade and well-drained but evenly moist soil. It branches profusely above and is tightly clumping with excellent form. This species will continue to produce sporadic branches of flowers until hard frost. Truly an excellent plant for the southeastern United States that thrives and provides vibrant color in our hot, steamy summer days. The late Dr. Larry Mellichamp of UNC-Charlotte, who is a relative of the original collector, shared this plant with us. (Hardiness Zone 7a-10b)
Scutellaria ocmulgee (Ocmulgee Skullcap) Much like the previous two species, this is a South Carolina and Georgia endemic. Scutellaria ocmulgee is found mostly along the fall-line in basic-mesic forests where it is restricted to soils with a circumneutral pH. It can be distinguished from S. mellichampii by the leaf bases which are cordate to broadly truncate at the base. It has a similar form and flowering season and thrives in average garden conditions in partial sun to sun. Our plants make a 2’ tall by 3’ wide clump with a branched and beautiful form. In June it is covered with large racemes containing hundreds of blue flowers. Ocmulgee Skullcap is the showiest of the Southern species we grow and rarely, if ever seen in cultivation. (Hardiness Zone 7a-10b)