One of our most colourful and popular winter/spring flowering plants is the polyanthus. These herbaceous perennials, often grown as annuals, are closely related to primulas and primroses and belong to the Primulaceae family.
It is believed that polyanthuses are the result of a cross between Primula veris, commonly known as cowslip and Primula vulgaris, the old English garden favourite with pale yellow flowers. The name ‘polyanthus’ was first seen in an English plant catalogue in 1687.
Polyanthus are admired for their many vibrant flower colours and decorative, scalloped-edged leaves that form basal rosettes.
The most popular polyanthus strain is the ‘Pacific Giant’ with clusters of large florets on tall, strong stems in a range of colours from rich, bright blues, pink, orange, yellow, bronze, purple, bright crimson and cream.
Polyanthus prefer a cool, rich, well-drained soil, preferably slightly alkaline, in dappled shade or at least having protection from very hot, dry and windy conditions.
Polyanthus excel when grown in clumps in woodland areas and cottage gardens. They combine well with early spring flowering bulbs and make a pretty scene when white alyssum is used as a backdrop for their vibrant colours.
As indoor plants they can be brought inside for a few days at a time to decorate and brighten a room.
Polyanthus are easy to grow from seed sown in late summer to early autumn. The seeds can be slow to germinate so be patient.
Scatter seed thinly in pots filled with a good quality seed-raising mix. Cover seeds lightly with a thin layer of this seed mix then press down gently with a board to ensure a firm contact between seed and soil.
The pots can have a glass cover put over them and placed in a shady spot. It’s important to keep the surface moist until seedlings appear which is usually in three to four weeks.
As the seedlings appear, repot into single pots but still keep them in a shady position until they have become well-established and ready to be planted out in the garden in April or May.
When transplanting seedlings, press the soil against the roots to ensure firm contact is made and keep the crown of the plants on the surface of the soil.
Apply a liquid fertiliser high in potash every two weeks from the bud stage to full flowering. The removal of dead flower heads will prolong flowering.
At the end of the season plants can be lifted carefully and replanted temporarily in a cool sheltered area under trees until next season.
They can be replanted into fertile soil at the end of March or early April for flowering the next season.
After four years it is advisable to start again with new seedlings or seed in a fresh bed to maintain this mass of bright colour in the garden.
February 10: The Westbury Garden Club’s ‘Summer Flower Show’ at the Westbury Town Hall, Lyall Street, Westbury from 1.30pm to 4pm. Afternoon teas available for $5. Entry is $2.
February 14: Longford Garden Club meets at the Christ Church Parish Hall, William Street, Longford at 7.30pm
February 15: The Launceston Orchid Society meets at the Newnham Uniting Church Hall, George Town Road, Launceston at 7pm.
February 20: The Australian Plant Society meets at the Max Fry Hall on Gorge Rd, Trevallyn at 7.30pm.
February 21: The Launceston Horticultural Society meets at the Windmill Hill Hall, High Street, Launceston at 8am.