Variations on a Theme: Primrose, Cowslip or Oxlip?

The third in my series of easily confused plants features some of the UK’s favourite spring wild flowers with a long heritage of lore.

While our native species of primula are well-loved, they are not as familiar and useful as they once were. Farmers are too busy to rub primroses on their cows’ udders on May Day to encourage milk. Most people who grow primroses near their doorway have forgotten the idea that they encourage faeries to bless the household. People no longer make tisty tosties from cowslip flower heads tied into balls, stems inwards, and hang them from sticks in their dozens to tell fortunes or wave in celebration. Few people have recently tasted cowslip wine. Cowslips are not common enough, and like all UK wild flowers, they are now protected.

But these wild flowers have such a dainty, delicate look, no matter how vigorously they grow, that they are rarely dismissed as weeds.

While primroses, cowslips and oxlips are not difficult to tell apart, they are often mistaken for each other. The country name for any wild primula, paigle, neatly avoided the problem.

Their leaves are similar: green, crinkled, and veined; roughly oval, tapering towards the bottom; and produced in loose rosettes close to the ground. As a result, the easiest way to tell wild primulas apart is to wait until they flower. This quick guide will narrow down the options:

Primulas have open flowers with heart-shaped petals

Cowslips’ narrow, bell-shaped flowers nod

• Wide open flowers suggest a primrose while narrower, bell- or trumpet-shaped, pendant flowers indicate a cowslip or oxlip.
• All three wild species of primula in the UK are commonly yellow. A pale, buttery yellow marks out a primrose or an oxlip while a golden yellow suggests a cowslip.
• If the flowers are held singly, the flower is a primrose or its hybrid. If flowers are held in clusters dangling on short stems from a central point at the top of one sturdy stem, you’re looking at a cowslip or oxlip or their hybrids.

Here’s a little extra detail on each:

Primrose (Primula vulgaris)

Each slender, hairy stem has only one flower, arching from ground level above and among the leaves. The plant forms a mound covered with a scattering of flowers that stay fairly close to the ground at around 10-15cm high. Flowers open wide hiding their calyxes (pale green leaf-like structures) behind them. Each petal is notched, giving it a heart shape.

Flowers may be quite sparse or liberally produced on well-established clumps. Primroses are commonly pale, greenish yellow with brighter yellow throats. You can also find pinkish forms or almost white ones growing wild. Synonyms include Primula vernalis.

Cowslip (Primula veris)

Sweetly scented flowers hang in clusters from sturdy stalks (known as scapes) held above the leaves at around 20-25cm high. Each scape is topped with between ten and thirty nodding flowers.

Cowslips are a richer, brighter shade of yellow with orange markings at the centre. The flowers are smaller than the primrose and have an elongated bell shape. Notched petals give the flower a wavy outline. The pale green calyx is very visible, wrapped loosely around the tubular end of the flower, in a marked colour contrast.

More rarely cowslips produce flowers in a range of warm, sunset colours, from orange to red. Seed strains of selected plants are available.

The cowslip’s popularity has given rise to a long list of folk names, including herb Peter, St Peter’s wort, bunch of keys, key of heaven, Mary’s tears, freckled face, fairy cups, golden drops, long legs and milk maidens.

Oxlip (Primula elatior)

Pale yellow, bell-shaped flowers are held in clusters on tall scapes up to 30 cm high. Flowers droop elegantly on one side only of the scape. Sadly oxlips are classed as near threatened and are rarely found growing wild in the UK other than in parts of South East England. Click here to see a picture on Wikipedia Commons.

Other options

Primulas are very attractive to pollinators and hybrids naturally occur whenever species grow close to each other in the wild.

False Oxlip (Primula vulgaris x veris)

If you believe you’ve found an oxlip growing wild in North West England, it’s more likely that you’re looking at a false oxlip – a hybrid that looks similar to the rare species Primula oxlip.

Signs of this are sturdy, upright plants with hybrid vigour and flowers that grow around the stem rather than just on one side. The flowers are variable, but tend to be more open, like a small primrose flower.

Other Primula Hybrids

While gardeners can choose from a fascinating array of selected forms, including double golden-yellow cowslips and hose-in-hose forms where a second flower grows neatly out of the first, some of these fancies are infertile and others will give rise to variable offspring.

One such curiosity is Primula Jack-in-the-green. Demure flowers lie flat against a collar of enlarged, leafy sepals. I’m showing a yellow flower but several colours are available.

For naturalising, stick to the species: Primula vulgaris, Primula veris or Primula elatior. All of these will form spreading colonies if you can provide the right conditions.