Why Ranunculus Grow Best In Containers: They Love Free Draining Conditions
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By PETER LICKORISH
Peter is a Horticulture Lecturer and self-employed Horticulturist, with a passion for diverse areas of the industry - from garden design to the science behind plant growth and propagation. He has completed the Royal Horticultural Society’s Master of Horticulture (MHort) Award and lectures on RHS courses at Bedford College.
IN THIS GUIDE
Though there are many Ranunculus species, many use the term ranunculus to refer to Ranunculus asiaticus, also known as ‘Persian Buttercup’ and sometimes simply referred to as ‘Garden Ranunculus’.
These plants are popular for their stunning flowers that come in a range of hues and there are a number of different varieties to consider.
These flowers can look great in a sunny and sheltered spot in the garden, or when used as cut flowers in displays.
They are extremely popular for weddings and other special events.
Are Ranunculus Suited To Pots?
Unlike our native buttercups, and other ranunculus plants commonly grown in more wild, organic and natural-style gardens, these ranunculi are more tender.
They are often cultivated in containers, sometimes in a sheltered and sunny spot outdoors, but more commonly, in the UK, in an unheated greenhouse.
In short, yes, you can grow garden ranunculus in pots.
In fact, this is the best way to grow them.
There are also other ranunculi that can work well in containers, including alpine varieties, but in this article, we’ll focus on the popular florist flowers – Persian buttercups.
Choosing Suitable Containers
One of the reasons that these ranunculi grow well in containers is that they enjoy free-draining conditions.
Containers can often provide free-draining conditions more effectively than in-ground growing, especially where there is heavier or clayey soil.
When choosing a container for these and any other plants that like free-draining conditions, it is important to choose one which will allow excess water to drain away freely.
You should make sure that there are drainage holes at the base and should also consider using feet to keep pots up and off the ground.
Terracotta pots can be an ideal choice and their colour can look good in a Mediterranean garden scheme or courtyard garden, where these flowers will look at home.
Compost For Ranunculus
These ranunculi will grow best in a medium made up of one part loam, one part leaf mould, and one part grit.
You can also use any peat-free, loam-based multipurpose compost with a grit added at a ratio of two parts compost mix by one part horticultural grit.
Potting Up Ranunculus
Ranunculus are grown from tubers or from seed.
Young plants can also often be purchased from garden centres or plant nurseries.
There are larger tubers that will provide more flowers and smaller tubers that will not produce as many.
The tubers should be planted with the pointed ends (finger-like protuberances) pointing down and should be set around 5cm deep.
Water well upon planting, but then hold off watering again until you see sprouts so that the tubers do not rot.
It is also a good idea to hydrate the claw-like tubers by soaking them for a few hours before planting.
How Many Plants Per Pot?
How many you can plant per pot will depend on which specific variety you are growing, and on the size of the container.
As a general rule of thumb, the tubers should be planted 30cm apart if they are larger ones, and around 10cm apart if they are smaller ones.
You could place 3-4 smaller plants into a 25-30cm pot.
Container Ranunculus Care
Place containers in a sunny and sheltered spot outdoors, or under cover in an unheated greenhouse or polytunnel, ensuring good light levels and ventilation.
“If you’ve got an open porch which receives sun for a good portion of the day, I can hardly think of a better plant for late spring impact,” shares Peter Lickorish, a Horticultural Consultant.
“If there’s one thing these plants hate, it’s sitting wet.
“A porch provides the rain shadow and shelter that these plants appreciate, whilst giving them the light they crave, unless north-facing.”
Water your ranunculi in pots whenever the top few centimetres of soil is dry to the touch, but make sure that excess water can always drain away freely and never allow waterlogged conditions to develop.
Add a mulch around the top of the container to retain moisture, ensuring that this does not touch the plants themselves and that the base of the stems remains free and clear or they may rot and develop fungal issues.
A grit mulch can be decorative and suppress pot weeds too.
Add a balanced organic fertiliser on planting and feed with an organic, potash-rich organic liquid feed every couple of weeks during the blooming period for best results.
Deadhead ranunculus regularly to encourage the plants to focus on flowers rather than seed production (unless you want to harvest seed to sow).
The plants should be left with their foliage intact after flowering.
Protect from early frosts with horticultural fleece or other protective measures if growing outdoors.
After the foliage turns yellow and dries up, store the plant in a cool but frost-free location.
“For seasonal containers, you can lift and pot tubers into 1 litre pots after flowering, for storing over late summer, autumn and winter, when they are dormant,” adds Peter.
Cease watering and then resume watering only once new growth emerges once more.
You can also lift and store the tubers in a dry, cool location to replant in spring.
These are not the easiest plants to cultivate, but many feel that the beauty of the flowers and their relative longevity when cut makes the effort worthwhile.
