The primrose has two types of flowers—pin-eyed and thrum-eyed. In pin-eyed flowers, the stigma (the top of the female reproductive organ, or pistil) is visible in the opening at the centre of the flower. It looks like a flat, green or yellow disk. In thumb-eyed flowers the anthers (the tops of the male reproductive organs, or stamens) are visible in the centre. The anthers look like long, greenish-yellow sacs.
Each type of primrose flower has both the female and the male organs; the only difference is the length of each organ. In nature, fertilization takes place between a pin-eyed flower and a thrum-eyed flower but not between flowers of the same type. Many relatives of the primrose also have pin-eyed and thrum-eyed flowers.
Cultivated primulas are derived from the wild species that grow in several European countries. Many are hybrids between different species. They come in a wide range of colours, patterns, sizes, and forms and often have more than five petals. Some even have multiple rows of petals. Many primulas have a pleasant scent.
Since there are so many different types of cultivated primulas, it's important for gardeners to check the growing requirements of the specific varieties that they buy. In general, the plants need rich soil which has a neutral pH or is slightly acidic. The soil should be moist but should also have good drainage. Soil containing humus and compost is best. Most plants grow well in a moderately cool environment with partial shade, but some varieties grow well in full sun. I've found the plants easy to grow in the mild climate where I live. Some types of primulas will grow in containers under the right conditions.
There are so many varieties of Primula available in nurseries that gardeners will almost certainly find at least one flower that appeals to them. The plants aren't hard to grow, although some types are more demanding than others. Primulas and primroses are attractive and delightful plants that add a beautiful splash of colour to a garden or a container. I always look forward
RE: Violas and Primulas.