Among the most beautiful American plants is a sturdy and distinctive shrub native in the Great Smoky Mountains of Tennessee and southward through the Blue Ridge. This is mountain stewartia (Stewartia ovata), and fortunately enough, it has a variety that is even more beautiful.
With their high Appalachian background, both these shrubs are dependably hardy, and in favorable conditions, they survive temperatures well below zero without damage.
Vexing changes in its botanical name have befallen this species, but gardeners are missing one of our finest native plants if these mishaps keep it from general use in home plantings.
The name formerly accepted was Stewartia pentagyna, and it should also be noted that the generic name was usually written Stuartia. However, Linnaeus established his genus number 758 as Stewartia, and must follow his spelling under the rules.
The variety grandiflora was first described in 1914 by the great British botanist and authority on woody plants, W. J. Bean. In the absence of a local name in its native mountains, it is known as showy mountain stewartia.
The flowers of this variety are larger than those of the parent species, frequently measuring four inches across. Even more exciting for gardeners, the stamens at the center have purple stalks. In mountain stewartia, the stamens are yellowish.
Both forms have sparkling white petals with beautifully crinkled edges.
The flowers vary considerably in size, some being as small as 2 1/2″ inches across. Homeowners should keep their eyes open for variations. It is entirely possible that as stewartia is grown more extensively, other fine varieties will be found.
July Is Stewartia Blooming Season
July is the time of year to become familiar with stewartias, as the blooming season of this group of shrubs and small trees starts in early summer. The most decorative kinds are at their best in July, just as the great wealth of spring-blooming subjects has finished flowering, and shrub plantings show the need for more variety to extend their period of beauty and interest.
Stewartias are tea family members, and their showy blooms with crinkled white petals open from round pearl-like buds are characteristic of this aristocratic group.
This trait is well borne out in Camellias and Franklinias. Like these relatives, also, stewartias do not burst into their full bloom in one concentrated display but have a succession of the round buds opening for several weeks. This prolonged bloom period makes them especially valuable for bridging the lapse between the principal garden display periods of spring and late summer.
Discovered In Georgia
Showy mountain stewartia was discovered in Georgia, where it grows naturally intermixed with its parent type along the banks of streams in the lower Appalachian region. Unless they are in flower, so that the color of the stamens can be noted, it seems practically impossible to distinguish one from the other.
The species itself is more abundant northward, particularly in eastern Tennessee, where it fairly lines the banks of some streams and makes dense thickets 15′ feet high or more. This is quite different from its behavior in gardens, however.
Stewartia shrubs planted as specimens, with room for development and in leafy acid soil, make well-balanced and gracefully branched plants about ten feet in height (or sometimes taller in very favorable conditions) and spread about two-thirds as much.
Their leaves are elliptic, from two and a half to five inches long, and characterized on vigorous shoots by a zig-zag arrangement.
The flower buds are borne singly on short stalks arising along the shoots from the leaf-axils. As each bloom expands, it is very artistically set off against the background of foliage. The leaves usually turn coppery pink tones before falling in October or early November.
Soil Requirements
Stewartias have very similar soil requirements to azaleas and camellias.
They thrive in a good supply of humus in light soil with abundant though not stagnant moisture. Heavy and poorly drained soils must be lightened with leafmold and sand and soggy conditions modified by whatever additional measures may be necessary.
On the other hand, dry or sandy soils should be liberally worked with humus to hold moisture.
It is also advisable to prepare holes at least two and a half feet deep and to make a generous reservoir of leafmold, old stumps, logs, or other humus-producing materials at the bottom to ensure extensive root development away from the dry top layer.
Lime, ashes, and fertilizers made up of lime, or ground limestone are harmful.
In full sunlight, stewartias develop into dense symmetrical specimens, sometimes nearly as broad as their height. Their habit is more sparse in the shade, and they tend to grow taller and more picturesque. Sunny locations produce more abundant bloom.
FGR-0750 by B Blackburn