Primulas and Primroses: Beautiful Spring Flowers
The Joy of Spring
One of the joys of spring is the appearance of beautiful primulas and primroses in gardens, containers, landscaped areas—and if you live in the right part of the world—in the wild.
In the UK, the English primrose is one of the first plants to flower in the spring. It has lovely pale yellow flowers that have a darker yellow centre. Many of the primrose's cultivated relatives also flower in the spring. They come in a huge variety of colours and forms and are very popular.
Some people might argue that some of the colours of cultivated primulas and primroses are too vivid, unnatural, and even garish, especially compared to the delicate hues of the English primrose. I think that the cultivated flowers are a beautiful sight, though. Where I live there are lots of evergreen plants, but the predominant colours of nature in winter are green and brown. It's so nice to see the cheerful flowers of primrose relatives in the spring.
The Primula Genus
It's helpful to understand the terminology used to describe primulas, primroses, and their relatives, since it can be confusing. Many hybrids have formed between the different types, which adds to the confusion.
Every living thing has both a common name and a scientific name. The scientific name consists of two words and is printed in italics. The first word in the name is the genus and is capitalized. The second word is the species. For example, Primula vulgaris is the scientific name for the English primrose and Primula veris is the scientific name for the cowslip.
The common name "primula" is sometimes used to refer to all species in the Primula genus. Some flower groups in the genus are often referred to by their own common name, however. I've chosen to discuss five of these groups: the primroses, polyanthus primroses, auriculas, drumstick primroses, and cowslips.
At least where I live, the polyanthus primose is the most commonly available primula. The word polyanthus means "having many flowers". The flowers often have rich colours. Some people drop the word polyanthus from the term "polyanthus primroses", creating a wider meaning for the word primrose. Others drop the word primrose from the term.
The English or Common Primrose
The primrose in the UK is sometimes known as the English or common primrose to distinguish it from other species of wild primroses. It's native to western and southern Europe and is found in hedgerows and open woodland. The "prim" in primrose comes from a Latin word meaning "first", which refers to the fact that primroses flower early in the year before many other plants.
Primrose leaves have a prominent midrib and a crinkled appearance. They form a basal rosette that lies close to the ground. The flowers emerge from the rosette on short stems and have five notched petals. Most primroses have yellow flowers, but the flower exists in a pink form as well.
The flowers and leaves of primroses are edible. They are eaten in salads and are also used to make a tea and a wine. In the UK it's now illegal to pick wild primroses or to dig them up, however. Varieties of the English primrose are sold by plant nurseries, so even people outside Europe can enjoy them if they have a suitable habitat and climate.
Some plants with the word primrose in their common name aren't members of the Primula genus. An example is the evening primrose, which belongs to the genus Oenothera.
Herbaceous and Evergreen Perennials
Wild primulas such as the English primrose are generally perennials, which means they appear in successive years. Many are herbaceous perennials. They have above-ground parts that completely or partially disappear at the end of the growing season. The underground parts survive, however, and produce new shoots in the next growing season. In evergreen primulas, the above-ground parts of the plant survive outside the growing season.
Cultivated primulas may be perennials, but some grow as annuals. In an annual plant, the above and below-ground parts die at the end of the growing season. A gardener will need to buy or grow a new plant in the next growing season if they want to enjoy the flowers again.
Pin and Thrum-Eyed Flowers
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.
Growing Cultivated Primulas
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.
In the United States, many primulas will grow successfully in zones 5 to 9 on the USDA (United States Department of Agriculture) Plant Hardiness Zone Map. This isn't true for all primulas, however, so the hardiness zone should be checked when buying a plant.
Garden and Wild PrimulasClick thumbnail to view full-size
Primulas can be grown from seeds, but like many people I buy them in pots and then transplant them. It's hard to resist buying a new plant when they are on display outside supermarkets in my neighbourhood. The goal of the colourful flower displays is to attract shoppers as they are about to enter the store. The trick certainly works on me. The garden centre near my home also sells interesting varieties of primulas.
I do grow some types of plants from seeds. The process is often more economical than buying bedding plants. Another advantage is that it's often possible to get a wider variety of plants via seeds than via bedding plants. In addition, there's something magical about seeing the first tiny leaves of a new plant emerging from the soil. It's hard or time consuming to get certain seeds to germinate, though.
Primula seeds take about three weeks to germinate. The American Primrose Society has instructions for growing primulas from seed for people who would like to try the process. A link to the society's website is given in the "References" section below.
Dividing a Mature Plant
When a primula plant has formed a clump of leaves after a few years of growth, it's sometimes divided into multiple plants. This usually improves its blooming ability. Some people divide the plant in spring while others do it in early fall. I've never tried dividing a primula myself, but the process seems to be quite easy.
The first step in division is to carefully dig around the plant and remove it from the soil with its roots as intact as possible. The plant is then gently teased into two or more plants by hand. The biggest leaves and any dead flowers are removed from each of the new plants and the roots are trimmed. The plants are then placed in the soil. The process is shown in the video below.
How to Divide and Grow Primroses
The primula group contains a large and varied group of plants. Auriculas are cultivated members of the genus that frequently have a colourful pattern on their petals. They were originally produced as a hybrid between two wildflowers—Primula auricula and Primula hirsuta. Today many different cultivars of auricula exist. A "cultivar" is a plant variety produced by selective breeding.
Auriculas are perennial and evergreen plants. Their fleshy leaves have no stem and are arranged in a rosette close to the ground. The leaves sometimes have a powdery white coating. The large flowers are born in a group which is positioned at the top of a tall flower stem.
Wild auriculas grow in an alpine habitat. They are sometimes known as mountain cowslips or bear's ear. The latter name comes from the shape of the leaves. The visible part of the ear in bears, humans, and other mammals is often referred to as the auricle. This fact may have given the auricula its species name.
Spring Care of Auriculas
The drumstick primrose is an attractive flower with a name that matches its appearance. The wild plant (Primula denticulata) is native to alpine areas of Asia. The species has become popular in a cultivated form. It has globular head of small flowers at the top of a tall stalk. The flowers are white, pink, or purple. The plant flowers in April and May. It's a herbaceous perennial.
The drumstick primrose is said to be easy to grow. Like many of its relatives, it requires moist but well-drained soil. It does best in partial shade but can tolerate full sun if it's well watered. It's hardy to zones 4 to 7. Once flowering has finished, the leaves continue to grow and spread out. The space requirement of the plant should be considered when it's planted.
The cowslip or Primula veris is both a wild and a cultivated primula. It bears a group of small, funnel-shaped flowers at the top of a tall flower stem. The flowers are usually yellow with orange spots near their centre, but they are occasionally red. The plant is native to Europe and Asia.
It's been suggested that the name "cowslip" originated from the plant's ability to grow in soil that is seasonally boggy and slippery. It also grows in drier areas, however, including pastures and grasslands. Another theory is that the name is derived from the effects of the cow dung found in places where the plant grows. The plant inhabits areas that are less shaded than primrose habitats.
The wild cowslip population in the UK decreased dramatically between the 1950s and 1980s, mainly due to intensive farming and herbicide use. Happily, the population is making a comeback.
As is the case for the primrose, cowslip leaves are used for salad greens. The flowers are used in wines and vinegars. They have a delightful fragrance that is used in the perfume industry. Cultivated forms of the plants are available for gardens. The Missouri Botanical garden classifies these as herbaceous or sometimes semi-evergreen perennials.
Anyone who collects plants for food must be certain of their identity and safety as well as their population status. Plants that are threatened or endangered shouldn't be collected. The plants should be gathered from an area that is free of pesticides and pollutants. Some plants should be left so that the local population can recover.
Attractive Garden Plants
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 to seeing them in bloom.
Pin-eyed and thrum-eyed common primroses from the Devon Biodiversity Action Plan
Information about polyanthus primroses from the Missouri Botanical Garden
Facts about auriculas from the American Primrose Society (The full name of the society is the American Primrose, Primula, and Auricula Society.)
Drumstick primrose facts from Cornell University
Primula veris or cowslip information from the Missouri Botanical Garden
Primrose information from the Memoral University of Newfoundland Botanical Garden
© 2013 Linda Crampton