Flower:

Dense clusters (panicles) of ¾ to 1-inch flowers are produced freely at the tips and lateral axils of new growth, sometimes double flowers (2 layers of petals) occur. Flowers have 5 oval to heart-shaped petals, typically pure white though occasionally light pink. Numerous deep yellow to orange stamens surround a short column of styles in the center.

Leaves and stems:

Leaves are alternate and compound with 5 to 9 leaflets, each ½ to 1½ inches long and 1/3 to 1 inch wide, finely toothed around the edges, sometimes just at the tip end, darker green and smooth on the upper surface, lighter green and hairy underneath. Leaflet shape is variable, egg-shaped to elliptic to broadest above the middle, rounded or wedge-shaped at the base, rounded or pointed at the tip. Entire leaf, including the stalk is 2 to 4 inches long.

Fused at the base of the leaf stalk is a pair of appendages (stipules) that have spreading hair-like bristles and often densely covered with glands. Stems and branches can be climbing, vine-like, or brambly, often cascading, a mature plant wider than tall. Stems are smooth but for sharp, dark and stout cat's-claw like thorns in pairs or more below the leaf nodes or scattered along the stem. Stems can reroot when branch tips come in contact with soil, sending up new shoots and producing dense thickets.

Fruit:

The berry like fruits (hips) are small and hard, about ¼ inch in diameter, round to oval, red brown or purple brown in color, each containing several seeds. A mature plant produces copious amounts of fruit—about a million seeds per year—which are viable for about 20 years.

Notes:

Multiflora rose was first imported as root-stock for hybrid tea and floribunda cultivars back in 1886. Later it was promoted by the US Soil Conservation Service for erosion control, living fences and wildlife habitat. This approach for new species introductions has been all too common in the human history of moving living organisms around the planet and still goes on, unchecked today, too often with disastrous results. While proving ineffective for erosion control it was also of little value for most wildlife except as a food source for a few generalist bird species that spread its seed everywhere, displacing beneficial flora. It did make a great living fence—dangerously impenetrable—but it didn't follow the human idea of staying in neat rows and quickly started invading the rural landscape everywhere, as it is not very picky about growing conditions, and often consuming entire pastures. Intensive use of herbicides and mechanical control (bulldozers sometimes required) are the only way to maintain productive habitat for any purpose. Minnesota is somewhat shielded by Multiflora Rose's lack of cold hardiness (hardy to zone 5) but some number of farmers down in Houston County have already experienced its wrath, and climate warming will only enhance its progression northward. There have been reports of its presence in several counties north of the Metro, but these are unconfirmed. It is, however, likely more prevalent than the existing Herbarium records indicate.