Flowers of climbing rose (Rosa setigera) of the Rose (Rosaceae) family, one of four native roses that occur in Arkansas, have a single layer of five pink (occasionally white) petals. The genus name is Latin for “rose,” the specific epithet, also Latin, means “bristle-bearing”. Climbing rose occurs in the U.S. from Texas to Wisconsin east to New Hampshire and the Atlantic and Gulf states. In Arkansas, it occurs in the northwestern three-fourths of the state. Another common name is prairie rose. Preferred habitat is fertile, dry-mesic to mesic soils, in partial to full sun along streams, woodland borders, fence rows, rights-of-way, and in prairie thickets.
Climbing rose produces long slender trailing or climbing arching stems and branches, along with fast-growing suckers that arise off the rootstock or off main stems. When supported by other vegetation or structures, plants may reach 15 feet tall. In open areas, stems arch so that mounds to 3 feet tall may form. When growing tips of branches touch the ground, roots emerge and a clonal plant is established. Stems and branches that extend along the ground without touching soil do not develop roots. New stems and branches, typically glabrous, are a light green the first year, later becoming light brown and woody.
Stems and branches of climbing rose have thick prickles which easily break off the epidermis when side-pressure is applied. Smaller diameter stems may have pairs of prickles just below leaf nodes. Larger diameter stems have a few to many additional prickles scattered along the internodes. The stout, down-turned prickles, to ⅜ inch long, have broad flattened bases (to ¼ inch) set parallel to the stem. Prickles, tapering to a very sharp hard point, hold stems and branches in place and provide some protection from herbivores.
Deciduous, odd-pinnately compound leaves, to 2 to 4 inches long and 2 to 3 inches wide, have three to five leaflets (one terminal leaflet and one or two pairs of laterals). Three-leaflet leaves tend to occur near the inflorescence, five-leaflet leaves away from the inflorescence and on more vigorous stems. Petioles (leaf stalks below lowermost leaflets) have a widened clasping base and lateral wing-like stipules that distally terminate with an acute out-flared ear-like tip (auricle). Margins of stipules are entire to finely toothed. Lateral leaflets have 1/16-inch-long petiolules (leaflet stalks); those of terminal leaflets may be ½ inch long. Abaxial (lower) surface of the petiole, rachis (midrib), and terminal petiolule bears stout to nearly invisible down-curved pricklets, along with stubby knobbed glandular hairs (stipitate-glandular pubescence).
Leaves have leaflets that are ovate to elliptic with rounded bases and acuminate apexes. Pinnate venation is conspicuous. Adaxially (above), leaflets appear rugose, the veins recessed below the blade surface. Leaflets are mostly glabrous, though fine pubescence may be present along abaxial veins. Revolute margins are serrate.
Inflorescences develop in mid-spring and consist of single or compound clusters of flowers that terminate new-growth stems and branches. A branch with a single cluster may have several to a half-dozen flowers. Larger stems may have up to 36 flowers on a half dozen floral branches further divided into secondary branches. A flower cluster on a secondary branch typically has three flowers, a terminal flower and two laterals with pedicels connecting at a common point. Central flowers of individual clusters are the first to bloom followed by those below. Flowering persists for several weeks to a month. Floral branches are subtended by smaller three-leaflet leaves. Within secondary floral branches, flowers are subtended by one to three lanceolate, half-inch-long bracts.
Flower buds are round in cross-section, with a constricted base, wide lower section and acutely pointed tip. Buds are protected by five narrowly triangular sepals that may have a few randomly-placed narrow lobes along their otherwise entire margins. Outer surface of sepals is stipitate-glandular as well as short tomentose. With anthesis, sepals become reflexed (falling off with fruiting).
Flowers are beautiful: 2½ to 3 inches wide, with five light to medium pink (fading to white) petals that typically overlap slightly in their lower half. Although scented, the flowers do not have the pleasant scent associated with most roses. (Occasionally, petals are white instead of pink.) The conspicuous androecium comprises numerous stamens with pale yellow filaments tipped by golden yellow anthers. (In the typical horticultural rose, most of the stamens are genetically converted to petals to create the double-multiple form.)
About 20 pistils are present. Their ovaries are sunken into the tissue of the receptacle (the stem tip), which forms an enclosing structure around them called a hypanthium. The styles form a tight column that emerges from the hypanthium at the center of the dense ring of stamens. Stamens, petals and sepals are attached to the summit of the hypanthium, sometimes called the hypanthial disc. The mature hypanthium with its enclosed seeds becomes a unique fruit: the rose hip.
Pistils that are fertilized mature into achenes (indehiscent, one-seeded fruits) within the developing hypanthium or hip, which becomes red and fleshy in late fall. The spherical, berry-like hip, ⅓ inch in diameter, retains the stipitate glands that were present even at flower bud stage and bears a scar of the hypanthial disc at its tip. Hips are eaten by various mammals and birds, thus effecting dispersal.
In a native plant garden, this climber would need regular training and trimming. It would do well inter-planted with various other native vines and shrubs where a screening effect is desired.
In addition to climbing rose, at least nine other rose species have been documented in the wild in Arkansas, of which three are native: Carolina rose (Rosa carolina), white prairie rose (Rosa foliolosa), and swamp rose (Rosa palustris). Of these three, Carolina rose and swamp rose have consistently pink flowers. Climbing rose can be distinguished by its climbing nature and rooting of branch tips. A non-native climber, multiflora rose (Rosa multiflora) has smaller white to light pink flowers and comb-like (fimbriate) hairs on its stipules.
Article and photographs by ANPS member Sid Vogelpohl