Primula: planting, cultivation, maintenance and companion planting

Botany

Primrose is a perennial plant that belongs to the Primulaceae family – it even gave its name to the genus: Primula. This large family comprises around 1,000 species of herbaceous plants, including Cyclamens and Lysimachia.

There are nearly 400 species of Primroses! They have a wide distribution in the Northern Hemisphere, with a significant centre of diversity in Asia. Indeed, nearly half of the species come from the Himalayas: it is no surprise that they are quite hardy in our climates. Three species are common in France, and you are likely familiar with them. They are Primula veris (Cowslip), Primula vulgaris, and Primula elatior.

The flowering of the Primrose often signals the end of winter and the beginning of fine days. Even its name indicates this: Primrose comes from the Latin primo: first, and vere: spring, meaning it is one of the first plants to flower in spring. Be careful not to confuse it with Cape Primrose (Streptocarpus saxorum), as its name can be misleading since it is not related at all!

Although perennial, the Primrose is often grown as a biennial and uprooted after flowering. However, it deserves to be left in the garden longer! So, once the flowers have faded, leave it in place, as it will bloom again each year. The flowers of horticultural varieties may, however, become paler and less vibrant over time.

The uses of Primulas are varied: some species thrive at the edge of ponds, others in rockeries or indoors. They can be planted in bowls, window boxes, or wide pots.

Primroses are generally rather low plants, rarely exceeding 20 to 30 cm in height. However, some species grow much taller. Thus, Asian Primroses or Candelabra Primroses bear tall flower spikes that can reach 1.20 m in height.

Primula officinalis – Atlas of Plants of France – 1891

The flowers begin to appear very early in spring, sometimes even in late winter. The most common ones (Primula acaulis) bloom from February. The Asian species bloom a little later, in early summer. If it does not suffer from summer drought, Primula acaulis may even bloom again in autumn.

The flowering of Primroses is very diverse, both in form and colour. The flowers are often large and rounded, with five petals, or more if they are double-flowered varieties. Horticultural varieties combine very bright colours. They can be yellow, red, blue, purple, pink, or white, often with a yellow centre.

Although Primroses are rather classic flowering plants, some species display a certain originality! Among them, we can mention Primula ‘Zebra Blue’ with its striking blue and white striped flowers. The Primula vialii stands out with its purple and red spikes, giving it a somewhat exotic appearance. There are also many double-flowered varieties, including Primula ‘Elizabeth Killelay’, which oddly combines red and white.

Primroses have rather ordinary leaves, which are entire and form a rosette at ground level. Their veins are often very pronounced, giving them a wrinkled appearance. Most species have evergreen or semi-evergreen foliage. It is deciduous in Primula japonica, Primula denticulata, and Primula vialii.

To better navigate among the many varieties, we divide Primroses into three main groups:

• Auricula: they have evergreen, smooth, often whitish and floury leaves. The flowers are very colourful and contrasting. They can be grown in rockeries.

• Candelabra: Candelabra Primroses bear tall flower spikes, with tiered flowering. They thrive in shade and cool soil. It is ideal to plant them near a pond. Their foliage is deciduous or semi-evergreen. In this category, you can find Primula bulleyana and Primula japonica.

• Polyanthus: this is a very important group with a great diversity of flowers. It includes Primula acaulis, the most common Primroses in cultivation.

The different species of Primroses

Primroses comprise nearly 400 species. Many varieties with original and vibrant flowers have been created from Primula vulgaris and Primula auricula. The botanical species also have significant ornamental interest.

• Primula elatior

This is the Oxlip, a small species quite common in France in woods and meadows, in moist and shaded environments. It bears delicate pale yellow flowers. Be careful not to confuse it with the Common Primrose, as it resembles it but is taller and has paler flowers.

Oxlip – Primula elatior

• Primula vulgaris

It is also known as Primula acaulis, Stemless Primrose, which means “stemless”. Indeed, its flowers are located directly at the level of the leaf rosette, making it much shorter than other species like the Oxlip or Common Primrose. It is the Garden Primrose, the most commonly cultivated species. The flowers of the type species are pale yellow and bloom from February. If the soil remains cool in summer, they may bloom again in autumn. Horticultural varieties feature much brighter colours: blue, pink, purple, yellow, or red! However, they always have a yellow centre to the petals. There are also original varieties with striped or double flowers, such as Primula vulgaris Belarina.

Garden Primrose – Primula vulgaris

• Primula veris

This is the well-known Cowslip, often called Buttercup. It is frequently encountered on forest walks, along paths. It is quite common throughout France and bears clusters of charming small bright yellow flowers. There are a few varieties with red or orange flowers, such as Primula veris ‘Sunset Shades’.

Cowslip or “Buttercup” – Primula veris

• Primula auricula

Known as “Bear’s Ear”, this Primrose known as “Auricula” offers a superb yellow flowering in spring, with a pleasant fragrance. It is a small, relatively low plant. Its leaves are rounded and sometimes covered in a white powder. It originates from the mountainous regions of Europe.

It has early on attracted the interest of horticulturists and collectors, who have created numerous varieties. Most of them are bicoloured, or even tricoloured. They are highly contrasting as they have the outer petals coloured (purple, red… and sometimes even green!), and a yellow or white round centre. The delineation and contrast of colours is striking. You may love them or not, but they certainly leave an impression.

Primula auricula ‘Argus’

• Primula vialii

It is called Marsh Primrose because it thrives in moist, even marshy environments. Plant it at the edge of a pond or at the edge of a woodland, but always in cool soil. It is very original. Its surprising purple and red flowering in elongated spikes gives it an exotic appearance. It is taller than most Primroses.

Marsh Primrose – Primula vialii – Photo Credit: PAP

• Primula denticulata

Easy to grow, the Denticulated Primrose will charm you with its beautiful flower pom-poms, reminiscent of Allium flowering. Its rounded flowers are borne on tall stems, giving the plant a very elegant appearance. They come in white, blue, purple, or pink. It is very robust, and its foliage is deciduous.

Denticulated Primrose – Primula denticulata – Photo: A. Karwath

• Primula bulleyana

This Candelabra Primrose hails from China. It bears long upright stems on which several tiers of very bright golden orange flowers are arranged, giving it a natural and airy look. Its foliage is deciduous. Plant it in rich, cool, even moist soil, and in partial shade.

Candelabra Primrose – Primula bulleyana[/caption>

• Primula sieboldii

Also known as the Siebold Primrose or sakurasô, this small Primrose originates from Siberia, Manchuria, Korea, and Japan, where it has been highly valued since the 17^th century. It bears a remarkable pure white, mauve, pale pink, or more pronounced flowering. Its petals, sometimes finely cut like lace, make it very delicate and elegant! Its leaves are deciduous. Plant it in cool soil and in partial shade.

Siebold Primrose – Primula sieboldii – Photo: Juni from Tokyo[/caption>

Our varieties of Primrose

Our Favourite Varieties

The Other Varieties

Primula secundiflora - Primrose

To discover! Interesting species due to its very delicate summer flowering, purple-red or violet. Small tubular flowers leaning towards the ground. It is one of the tallest species.

• Flowering time July, August
• Height at maturity 80 cm

See the product sheet

Primula japonica Alba - Japanese Primrose

Candelabra primrose, particularly robust and quite tall. Pure white flowering, with a yellow eye. Enjoys moist soils and shaded exposures.

• Flowering time June to August
• Height at maturity 60 cm

See the product sheet

Primula japonica Millers Crimson - Japanese Primrose

Candelabra primrose with intense pink flowering, almost red. Robust and tall variety. Will thrive at the edge of a pond or in the undergrowth.

• Flowering time June to August
• Height at maturity 60 cm

See the product sheet

Primula pulverulenta - Mealy Primrose

Candelabra primrose with purple flowering. Deciduous foliage. Prefers moist ground.

• Flowering time July, August
• Height at maturity 60 cm

See the product sheet

Primula denticulata Rubin - Primrose

Ball-shaped flowering, ruby red. Deciduous foliage.

• Flowering time April to June
• Height at maturity 40 cm

See the product sheet

Primula denticulata Alba - Primrose

White ball-shaped flowering. Deciduous foliage.

• Flowering time April to June
• Height at maturity 35 cm

See the product sheet

Primula vulgaris Belarina Cobalt Blue- English Primrose

Remarkable for its intense blue flowering.

• Flowering time February to May
• Height at maturity 15 cm

See the product sheet

Primula x hybrida Elizabeth Killelay

Very original flowering! Red petals edged with white.

• Flowering time April to June
• Height at maturity 15 cm

See the product sheet

Primula juliae Wanda - Primrose

Small spreading primrose, with violet flowers. To be cultivated in rockeries.

• Flowering time April to August
• Height at maturity 10 cm

See the product sheet

 

To choose your primroses well, follow our advice: “Primroses: which variety to choose”

Young plantation

Where to plant?

Grow your Primroses in a cool but well-drained, humus-bearing soil rich in organic matter. They do not like compacted, heavy soils, nor those that are too dry or waterlogged in winter. If your soil is heavy, add coarse sand or gravel to improve drainage. They prefer neutral or acidic soils, although the Common Primrose enjoys calcareous soils.

Avoid full sun! Instead, plant them in partial shade: take the opportunity to add colour at the base of trees or at the edge of woodlands. However, Primula denticulata enjoys the sun.

Some will thrive in pond edges: this is the case for Primula florindae, Primula vialii, or Primula bulleyana. These Asian Primroses particularly favour moist soils! As for Primula auricula, plant it in rockeries or in a pot.

To learn more: Growing a Primula auricula in a pot.

The Auricula Theatre: a lovely way to showcase a collection of Primroses – Photo: tpholland

When to plant?

Plant your Primroses preferably in autumn, in October or November. Planting is possible until March.

How to plant?

To create beautiful colourful clumps, we suggest planting them in groups of three or five young plants of the same species. Do not plant too many, as their very bright flowers could become overwhelming.

Soak the root ball in a basin filled with water. This will help the plant establish itself. In the meantime, work the soil with a spade, breaking up clumps and removing the largest stones. Add compost or well-rotted manure to encourage the growth and flowering of your Primroses. Also, add gravel or coarse sand if your soil is heavy to improve drainage. Dig and place the root ball. Replace the soil and gently firm it down with the palm of your hand. Water generously.

Once established, Primroses can live for up to ten years if not affected by diseases or pests. However, the flowers of horticultural varieties often lose their vibrancy and become duller over time.

Maintenance

We invite you to wear gloves when handling Primroses: they contain primin, a substance that can cause allergic reactions in some individuals.

Primrose is relatively easy to care for. Add some fertiliser at the end of winter to encourage flowering. Horticultural varieties, especially those with double flowers, are more demanding in terms of fertiliser and watering. Regularly remove faded flowers. Divide your Primrose plants every three years to give them more space and prevent them from becoming exhausted.

Water once or twice a week if you are growing your Primroses in pots, window boxes, or indoors. We also suggest watering those grown outdoors, especially during prolonged dry spells. Ensure to keep the soil cool, while avoiding excess water that could lead to root and collar rot. Consider mulching with a layer of leaves to help the soil retain its moisture.

The leaves of Primroses are sometimes nibbled by snails and slugs! And birds are fond of their flowers, with their sweet nectar. Primroses are also susceptible to red spider mites and aphids.

Primrose Propagation

You can multiply your Primroses by sowing or by clump division, but we recommend the latter technique, which is easier to carry out and quicker than sowing. However, be aware that some Primroses tend to self-seed and can naturalise in the garden!

Sowing

Sow under cover at the beginning of spring, in March or April. Sowing is a bit tricky, but you will succeed by following a few simple rules.

The Primrose needs a period of cold to break its dormancy and germinate. Place your seeds for one week in the refrigerator. Similarly, if you do not wish to sow them immediately, keep them in the refrigerator to prevent them from drying out.

Mix the potting soil with a bit of sand to obtain a well-aerated substrate. It should also be poor, preferably choose a potting soil without added fertiliser.

Take a seed tray, place a layer of gravel or broken pot at the bottom to facilitate drainage. Fill the tray with substrate and firm it down. Sow the seeds, but do not cover them! Firm gently and then water with a fine spray (you can use a misting bottle). Place the tray in a bright and cool place at a temperature between 10 and 15 °C (it should never exceed 20 °C). Ideally, set it outside, in the shade.

The following month, as soon as they have several leaves, you can prick out the young plants into buckets. Handle them gently to avoid damaging their roots. You can plant them in the garden in autumn, starting from September. Be sure to keep the soil moist during these operations by watering regularly.

Primroses will not flower in the year of sowing; you will have to wait a year!

Clump Division

Divide your Primroses in autumn, from September or October, once the Asian species have finished flowering. Division is possible until March. We recommend dividing the clumps every three years to give more vigour to your Primroses.

Gently unearth the plant. Remove the excess soil by shaking the root ball. Divide it by separating the roots. Trim the longest roots and a few leaves to balance the plant and encourage the growth of new leaves and roots. Replant in a new location, then water generously.

→ Learn more in our tutorial: How to divide primroses?

Associating primroses in the garden

The flowering of Primroses is highly varied, allowing for multiple combinations! With their vibrant colours, they bring a lot of dynamism to the garden, but they can also overwhelm and dominate the space. Use them with care, in small groups, and pair them with plants that have softer flowers or decorative foliage such as grasses, ferns, and Heucheras.

Asian Primroses easily find their place in naturalistic borders. They are wonderful for enhancing the edge of a water feature. Our native wild species, such as Primula veris or Primula acaulis, also integrate very well into natural and wild gardens. They bring a lovely touch of colour, much appreciated in spring.

Stemless Primroses and Muscari: a very natural combination

They thrive in partial shade and will do well at the woodland edge, alongside Epimediums, Persicarias, or ferns. Alpine species, such as Primula auricula or Primula marginata, can be planted in rockeries. They prefer well-drained soils. Plant alongside some Saxifrages, stemless Gentians, or Carex.

Japan: Japanese Primroses (Primula japonica) in Nikkō (Japan) – Source: Wikipedia

Discover even more ideas in our association sheet : “Primroses – 7 ideas for garden pairing”