Ricinus communis

How to grow castor oil plant

Find out all you need to know about growing the castor oil plant, Ricinus, in this detailed Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Sow
Sow

Do not Sow in January

Do Sow in February

Do Sow in March

Do not Sow in April

Do not Sow in May

Do not Sow in June

Do not Sow in July

Do not Sow in August

Do not Sow in September

Do not Sow in October

Do not Sow in November

Do not Sow in December

Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do not Plant in April

Do Plant in May

Do not Plant in June

Do not Plant in July

Do not Plant in August

Do not Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does not flower in May

Plant does not flower in June

Plant does flower in July

Plant does flower in August

Plant does flower in September

Plant does not flower in October

Plant does not flower in November

Plant does not flower in December

Cut back
Cut back

Do not Cut back in January

Do not Cut back in February

Do not Cut back in March

Do not Cut back in April

Do not Cut back in May

Do not Cut back in June

Do not Cut back in July

Do not Cut back in August

Do not Cut back in September

Do Cut back in October

Do not Cut back in November

Do not Cut back in December

Ricinus, the castor oil plant, brings exotic structure to gardens in summer with its dramatic foliage. The bold, glossy palmate leaves, reddish-purple in colour, are the main attraction. It looks great teamed with hot coloured plants and contrasting foliage in an exotic or jungle-style border.

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A native of tropical climates, Ricinus is usually grown as an annual in the UK and suits both containers and borders.

Take a look at our handy Ricinus Grow Guide.

The bold, glossy palmate leaves, reddish-purple in colour, are the main attraction.

Where to plant castor oil plant

Grow in containers in free draining, soil-based compost in full sun, or in a well-drained sunny border. Plants grown on poorer soils tend to produce more flowers, and the foliage is less abundant.

Ricinus communis seedlings
Ricinus communis seedlings

How to plant cast oil plant

Please note, the seeds are poisonous, so wear gloves when handling. Seeds must be sown early in the year, and ideally soaked for a few hours beforehand. Fill individual pots with seed compost, sow the Ricinus seeds and place in a heated propagator to germinate. Seeds need 15 to 20°C and should germinate in two to six weeks. Pot on when seedlings are large enough to handle and move outdoors or plant up into containers or borders when all danger of frost has passed.

Ricinus communis
Ricinus communis

Looking after castor oil plant

All parts of Ricinus communis are highly toxic so it’s very important to wear gloves when handling – it can irritate skin and eyes. Water plants regularly and feed with a liquid fertiliser every month. Plants are generally fast growing – Ricinus communis reaches 8-12m in height in tropical climes, but in a British garden, it is much smaller. Plants may need staking. Deadhead flowers if you don’t want to collect the seed. At the end of the season, discard plants on the compost heap, or move plants to a covered area under glass to grow on as a conservatory shrub.

Ricinus communis seedlings
Ricinus communis seedlings

Propagatng castor oil plant

Ricinus communis produces greenish-yellow flowers and spiny round seedpods. You can save the seed but they are notoriously toxic. Bearing this in mind, you might choose to deadhead the fluffy blooms before seeds set.

Ricinus: problem solving

Ricinus is generally disease-free outdoors. If grown under glass, it may fall prey to the usual greenhouse pests such as red spider mite.

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Ricinus communis 'Carmencita'
Ricinus communis ‘Carmencita’

Ricinus varieties to try

  • Ricinus communis ‘Carmencita’ – with large, deep bronze-red, palmate leaves and bold red female flower spikes in summer.
  • Ricinus communis ‘Red Giant’- this variety has brighter red leaves and seed heads. Leaves appear green at first, turning red as they mature.
  • Ricinus communis ‘Impala’ –  the foliage is typically striking, but in this variety, the flowers are equally eye-catching. They appear as clusters of creamy flowers, and are followed by brilliant red spiky fruits.