Height 15-30cm (6-12in)
Planting distance 30cm (1ft)
Flowers early to late spring
Partially shaded site
Short-lived perennial treated as biennial
Primula is an enormous genus of hardy and half-hardy perennials, but one group within the genus, the polyanthuses, are usually grown as biennials for bedding.
The polyanthus has been popular since its introduction in the 19th century. It is developed in part from the common primrose (Primula vulgaris) and has retained the characteristic bright green, corrugated leaves of that species. But only with the development of the large-flowered hybrids has the polyanthus become widely used in bedding. These large-flowered hybrids produce blooms in compact long-lasting clusters on tall sturdy stems 23-30cm (9-12in) high. Theappear from early to late spring in a wide spectrum of colours.
Several seed selections are available, usually mixed strains.
‘Crescendo’ has giant flowers in shades of primrose, yellow, red, pink, blue and white, and reaches 30cm (1ft) high.
‘Fancy Shades Mixed’ is about 18cm (7in) tall, with flower heads in shades of bronze, peach, amber, rose-pink, cream and white.
‘Giant Superb Mixed’ has large flowers on sturdy 20cm (8in) tall plants; colours include white, yellow, crimson-red and blue.
‘Jackpot Mixed’ has short flower stems topped with yellow-eyed blooms in full colour range.
‘Pacific Giant’ has enormous blooms coming in a wide range of colours. The plants reach 30cm (1ft) high.
‘Spring Rainbow’ grows 20cm (8in) high and has several stems to each plant, bearing dense clusters of flowers from scarlet, rose, pink and orange to yellow, white and blue.
Hybrids bred from Primula vulgaris are smaller than polyanthus primroses, up to 15cm (6in) tall, with clusters of often stemless flowers. They include:
‘Husky’, with an abundance of lavender, pink, rose, blue, yellow and white flowers.
‘Rosebud Mixed’ has clusters of rose-shaped, frilled flowers, in pink, red, apricot and orange edged with gold or silver.
‘Wanda Hybrids’ bloom prolifically and are exceptionally cold-resistant. Strong bright colours and often bronze foliage. Available as mixtures or in single colours.
Sow the seeds under glass between spring and mid summer. Germination is often erratic and slow. Prick out in a cold frame or into boxes of potting compost when the seedlings are large enough to handle. Plant out in autumn, setting the plants 30cm (1ft) apart. Polyanthuses grow best in a partially shaded site in moist fertile soil.
Pests and diseases
Slugs and snails sometimes eat the flowers.