Approximately 450 species of primroses ( Primula species) exist, according to the American Primrose Society's website. The perennial plant's flowers are rosette-shaped with leaves that sport a crinkly texture and scalloped edges -- a few varieties have a light fur covering.
Flowering Time Frame
Clusters of up to 25 flowers in a wide array of colours sprout from the centre of the plant. The flower stalks stand only 6 inches in height. During the winter months the plant produces an abundance of non-stop flowering when kept as a houseplant.
Outside Flowering Primroses
Primroses planted outside flower in the late winter and into spring when the weather is still relatively cold but some hybrids produce flowers in the midsummer months in cool regions. The plant prefers that the daytime temperature remain below 26.7 degrees C to adequately flower.
The primrose does best in U.S. Department of Agriculture hardiness zones 4 to 8, according to the Floridata website. The plant requires organically rich soil that is moist but not overly waterlogged. A primrose left in standing water will quickly die. The plant grows best in filtered sunlight or partial shade.