How to grow ranunculus (Persian buttercup)
Advice on growing Persian buttercup (bedding ranunculus) in our Grow Guide.
Ranunculus is a large and diverse genus of plants suitable for growing in a wide range of garden locations. Popular species include the moisture-loving and aquatic species water crowfoot (Ranunculus aquatialis) and greater spearwort (Ranunculus lingua). There are hardy perennials for borders such as Ranunculus aconitifolius, alpine species for rockeries such as Ranunculus alpestris, and the native wild meadow buttercup (Ranunculus acris) for wildflower meadows.
Persian buttercup (Ranunculus asiaticus) is often referred to as bedding ranunculus as it's a superb flower for adding a splash of colour to pots and borders, although blooms are relatively short-lived, lasting for around six weeks. Frost tender, Persian buttercup grows from bulb-like corms (often called bulbs) and flowers on short, sturdy stems around 30cm high, above finely divided fresh green leaves.
Ranunculus asiaticus flowers between late spring and early autumn, depending on when the tubers are planted. Up to four blooms are borne on branching stems. Most are fully double, packed with petals, and are almost rose-like in appearance. They make excellent cut flowers.
After flowering, Persian buttercup growth dies back. Although they are perennials, and the corms can be dried and replanted the following year, Persian buttercups don't reflower reliably, so are best treated as annuals and grown for one season only.
Where to grow ranunculus
Ranunculus grows well both in containers and the ground. Make sure that the soil is free draining, and that they are planted in a sunny spot that's sheltered from cold winds. If planting corms in autumn, plant in pots under cover and grow them on indoors until all danger of frost is over.
Well-drained soil or potting compost is essential as the tubers tend to rot in heavy or waterlogged conditions. In pots, use a peat-free multi-purpose potting compost mixed with around a quarter by volume of coarse grit or perlite, then stand pots on gravel or raise just off the ground so excess water drains away freely. If planting in the ground, make sure the soil is well drained. Raised beds are ideal for growing ranunculus as the soil usually drains well.
When to plant ranunculus
Planting time of ranunculus bulbs depends on whether they are planted under cover or outside. Under cover, in a frost-free, cool place such as a greenhouse, porch, or polytunnel, plant in pots from early autumn to early winter. For growing outdoors, plant from late spring to early summer. (Bear in mind that those planted from late spring will flower the following year.)
How to plant ranunculus
Plant ranunculus bulbs in autumn in pots under cover to flower the following summer. Soak ranunculus bulbs in water for 24 hours before planting with the pointed claw-like part facing downwards. Plant 5cm deep and 10cm apart. Transplant after risk of frost has passed to a sheltered, sunny spot in moist but well-drained soil. Discard once flowering has finished.
Ranunculus can also be planted in containers.
How to propagate ranunculus
Sow seed in September in small pots or trays with individual cells, and cover with a light layer of compost. The seed will need a temperature of around 15ºC to germinate. They also need to be kept moist throughout winter. Pot on when the seedlings have four true leaves. Although you can grow ranunculus this way, it is easier to grow them from corms.
How to care for ranunculus
Under cover, ranunculus is best grown cool so only heat the greenhouse as much as necessary to keep the temperature above freezing. In spring, once the frosts are past, move the growing plants outside to give beautiful early summer blooms. When harvesting the blooms for cut flowers, pick before the blooms are fully open to give the longest vase life.
Water regularly once growth appears, aiming to keep the compost moist, but take care not to over-water.
Feed ranunculus when flower buds start to form. Use a liquid fertiliser high in potash and apply every 10-14 days.
Deadhead regularly to encourage the plant to produce more flowers.
Pests and diseases
- Yellow leaves and rotting corms are a symptom of waterlogged soil or compost. Avoid overwatering, being especially careful when watering ranunculus in containers as ranunculus are prone to root rot.
- Grey mould (botrytis) indicates a lack of ventilation around the plants. You may notice grey to brown mould on a plant's leaves, buds or flowers, and these may shrivel up. Remove any affected foliage and flowers immediately and destroy. If growing in a greenhouse, increase ventilation to reduce humidity.
Advice on buying ranunculus
- Buy large, good quality ranunculus bulbs from a reputable supplier
- Check bulbs are firm with no sign of rot
Where to buy ranunculus
Ranunculus varieties to grow
Ranunculus asiaticus is the Persian buttercup species and hybrids of it are very popular for filling containers with summer colour. Height x Spread: 30cm x 15cm
- Buy Ranunculus asiaticus from J Parker's
Ranunculus 'Amandine Bonbon' – the Amandine series is known for its large flowers and there's many cultivars to choose from in shades including pink, orange and white. H x S: 38cm x 15cm
- Buy Ranunculus 'Amandine Bonbon' from Rose Cottage Plants
Ranunculus asiaticus 'Aviv Red' – one of the Aviv series, with large, bowl shaped flowers. 'Aviv Red' has deep red flowers with pink in the centre, but there are also pink, orange and white varieties. H x S: 30cm x 15cm
- Buy Ranunculus 'Aviv Red' from Crocus
Frequently asked questions
Does ranunculus come back every year?
Although Persian buttercups are tuberous perennials, they don't come back every year. There may be some tubers that grow again, but they won't reflower reliably and so are usually treated as annuals and used for bedding or to provide cut flowers.
Do ranunculus multiply each year?
Ranunculus are half hardy and the climate in Britain means that you can't rely on ranunculus multiplying or reflowering.
