Rose pink (Sabatia angularis) of the Gentian (Gentianaceae) Family, also known as common rose pink* and rose gentian, is an herbaceous annual or biennial. It occurs naturally throughout much of the eastern US from eastern Texas and southeastern Kansas to Michigan, New York, Massachusetts, and thence south and east to the Gulf and Atlantic Coasts. In Arkansas, the species occurs throughout much of the state except for portions of the Mississippi Alluvial Plain. The plant grows in full to partial sun in moist to dry glades and prairies and margins of woods and thickets. The genus name is based on the 18th century Italian botanist Liberato Sabbati. The specific epithet refers to the plant’s four-sided stems.
Rose pink produces a basal rosette of leaves from which one or several stems grow up to 3 feet tall. The entire plant is the same spring-green color, glabrous and shiny. Stems are square in cross-section with flexible narrow wings at corners. Branches, occurring along upper portion of main stem, are also squared and winged, as too are smaller sub-branches.
Photo 1: Basal rosette of leaves of rose pink in mid-March appears somewhat ruffled.
Branches grow from axils of upper stem leaves, typically from both leaves at a leaf node (thus primarily opposite branching). Branches, which have their own opposite leaves, produce a few to about eight paired pedicels that bear flowers. Branch divisions, up to the pedicels, are subtended by paired, elongate to linear leaves or bracts. Spacing of leaf pairs (and related branching) remains fairly constant along the main stem.
Leaves of rose pink are ovate to ovate-lanceolate, with lower leaves being larger and more rounded. Leaves are clasping (in the case of lower larger leaves) to sessile (in the case of upper smaller leaves). Bases of larger leaves are heart-shaped with leaf bases overlapping around the stem. Leaves are entire (margins not toothed). Larger stem leaves are about 1½ inches long and 1 inch wide.
Photo 2: In early June, stems of rose pink may be two feet tall. Stems, branches and pedicels are winged along their four angled corners.
Photo 3: In late June, the showy flowers make rose pink stand out among other plants.
Flowering occurs in early summer. The overall shape of the inflorescence is pyramidal and loosely open due to upright growth pattern of branches and pedicels and due to lower branches being longer. Flowers, up to 1 inch across, have five oblong to obovate pink corolla lobes joined at their bases to form a short tube. Each flower has five stamens with yellow anthers, a superior ovary with a divided stigma, and a green calyx. The calyx has five linear-lanceolate lobes about half the length of the corolla lobes.
The corolla lobes are primarily pink, but have a greenish yellow, triangular segment at their bases with a reddish outline on two sides. That greenish yellow marking of the corolla lobes and of the ovary, along with the reddish outline, produces a prominent star design. Flowers of rose pink may occasionally be white and may also occasionally lack a prominent red border around the central “star.”
Photo 4: The divided stigmas of rose pink can be seen in several flowers. The calyx lobes are positioned away from flower bud before corolla unfurls.
After flowering, the pedicels (flower stalks) may become brown while seed capsules remain green. The elongated cylindrical seed capsules, about 1/3 inch long and lacking internal partitions, contain many tiny seeds that can be wind dispersed or carried by flowing water.
Photo 5: In mid-August, rose pink plants wither, but seed capsules continue to mature.
In a garden, rose pink would not be especially noticeable until flowers appear, but then would be an eye-catcher. Plants seem to be content in various soil moisture levels in fairly sunny to full sun sites. Plants are short-lived but can seed around (note, though, that offspring may come up in different areas of the garden than where the parents were growing if allowed to self-seed). Rose pink does not seem to be favored by deer.
* Five other species of Sabatia occur in Arkansas, all with pink flowers, and have some common names that are similar to those noted herein for Sabatia angularis.
Article and photographs by ANPS member Sid Vogelpohl
Arkansas Native Plant Society 