Canada

Prairie rose

Rosa arkansana

Flower. 1 to 4 flowers typically form at tips of new, ground shoots and occasionally at tips of second year lateral branches of older woody stems. Flowers are 11/2 to 2 inches across with 5 broad, rounded petals with wavy edges often notched at the tip. The color can range from nearly pure white to deep rose pink and often strongly bi-colored. Numerous yellow stamens surround the shorter styles in the center. The sepals are narrow lance-like, 1/2 to just under 1 inch long, rounded at the base, the outer surface smooth. Flower stalks are smooth.
Leaves and stem. Leaves are alternate and compound with 9 to 11 leaflets, occasionally 7. Leaflets are 3/4 to 1 1/4inches long and 1/2 to 3/4 inch wide, generally elliptic or widest above the middle (obovate), rounded or blunt at the tip, with serrated edges except at the base. Leaf stalks are 1/2 to just over 1 inch long and hairy. 2 wing-like appendages (stipules) are at the base of the stalk, and sometimes have a few scattered glands around the edge of the tip end. Upper leaf surface is dark green and hairy to smooth, the underside light green and hairy.
First year flowering stems are green turning red the following season, mostly simple, typically spreading to ascending. Lateral branches are produced on older woody stems and are weak and often don't flower. Both first and second year growth bear stiff, slender bristles of unequal size.
Fruit. The round berry like fruits (rose hips) are about ½ inch in diameter, turning bright red in late summer.
Inside the hips are several light brown seeds that are oval to egg-shaped, about 1/6 inch long, with a few long hairs at the ends and across the surface.
Notes:
Prairie Rose establishes from seeds distributed by wildlife (typically birds) that have consumed its nourishing fruit. Once established, they spread out from underground rhizomes, often forming colonies. Above ground stems rarely persist for more than a few years before dying back to be replaced by new shoots. All three of Minnesota's native roses appear very similar at first glance. Two primary indicators for R. arkansanaidentification are its preference for open, sandy prairie and small size which rarely gets over 18 inches and more often just 10-12 inches. Like Prickly Wild Rose (Rosa acicularis) it has prickles on both new and old growth but it lacks the glands found on the leaf stalks of the latter, and their natural ranges barely overlap along a NW to SE line through central Minnesota. Prickly Rose is also a rather taller plant. Smooth Wild Rose (Rosa blanda) shares the range of R. arkansana throughout the state, but as it name suggests, Smooth Rose lacks bristles on its new growth—it's a mid-sized to tall shrub whose bristly, woody stems persist producing showers of flowers for many years.