Horticulture Magazine

Ranunculus Asiaticus ‘Persian Buttercup’ Plant Care

beautiful persian buttercup flowers in white, orange and red hues

Garden Ranunculus Overview

Official Plant NameRanunculus asiaticus
Common Name(s)Persian Buttercup, Buttercups
Plant TypePerennials / Annuals
Native AreaEurasia
Hardiness RatingH4
ToxicityToxic to some pets
FoliageDeciduous
FlowersBeautiful blooms in various hues
When To SowMarch, April
Plant OutMay, June, July, August, September
Flowering MonthsJuly, August, September
Sunlight

Preferred
Full Sun or Partial Shade

Exposure
Exposed or Sheltered

Size

Height
0.5 – 1M

Spread
0.1 – 0.5M

Bloom Time
June – August

Soil

Preferred
Most soil types

Moisture
Moist but well-drained

pH
Acidic / Neutral

Would you like to see fully double bowl-shaped blooms with row after row of neatly-arranged wafer-thin petals in your garden?

And, oh, the colours – snow-white, ruby red, dark violet, or gradated flame orange or with fine purple edging!

On top of it all the long-blooming flowers rise above a perfect backdrop of feathery foliage, courtesy of Mother Nature.

Be introduced to Garden Ranunculus.

What is ‘Ranunculus’?

So what’s ‘Ranunculus’? That very much depends on whom you ask.

If you ask a botanist, you will be informed that it is a huge genus in the Plant Kingdom comprising over 600 species of quite a variety of flowering plants.

Now if you ask an old-line gardener in the Midlands they will promptly tell you about buttercups – the Meadow buttercup, the Creeping Buttercup, the this-or-that buttercup.

But if you ask a floriculturist or florist they will tell you that these are gorgeous rose-like flowers that are hybrids, cultivars, or hybrid-cultivars of species Ranunculus asiaticus. 

Though we provide a brief introduction to the Ranunculus genus, this guide has a focus on the floriculturist’s definition of the Ranunculus plant, which is also known as ‘Garden Ranunculus’.

It is also called ‘Persian Buttercup’ though this is incorrect and confusing because that is the common name of the parent species Ranunculus asiaticus.

Ranunculus is a member of the (surprise!) Family Ranunculaceae which comprises of 43 genera, many of which include attractive flowering plants that deserve to be better known.

At least Genus Ranunculus does not suffer from lack of recognition. Buttercups, those charming rascals of the Plant Kingdom, are notorious for their “give ’em an inch and they’ll take a yard” habit.

Buttercups are adept colonizers but this annoying habit is surely somewhat compensated for by their simple and pretty flowers.

Ranunculus asiaticus cultivars, on the other hand, could not be more different. Their blooms are beautiful but very un-simple. And far from being colonizers or ‘taking a yard,’ these plants are not the easiest ones to grow.

Ranunculus flowers in White, Picotee, Pink, Red, Dark Violet
An Amazing Range of Hues: White, Picotee, Pink, Red, Dark Violet

Now What’s ‘Garden Ranunculus’?

Ranunculus asiaticus cultivars or Garden Ranunculus are herbaceous deciduous perennials that are effectively annuals in cold climates.

Bear in mind, though, that other species – besides Buttercups – in this genus are starkly different.

Some are fully cold hardy, others grow in poor soil, and yet others are water-loving aquatic plants. Ranunculus are none of these things.

They are highly-cultivated ornamental plants for well-manicured gardens. There is one and only one reason to grow these plants: the blooms.

You would not guess that reason from the mother species, Ranunculus asiaticus, though. It bears a pretty but simple single flower that is quite similar to European Buttercups.

This plain flower is all of 5 centimetres wide and comes in colours from yellow through orange to pinkish-red.

To the far extreme, Ranunculus blooms are sensational bouquet flowers, typically from 10 to 12.5 centimetres, that are often used as centrepieces in high-end floristry.

Nominally fully double flowers that are somewhat similar to roses, Ranunculus blooms are composed of neatly-arranged series and series of just-overlapping wafer-thin petals that make concentric circles.

Pink Garden Ranunculus
Garden Ranunculus

These blooms have pastel or bright hues with a satiny sheen, and last for a week or more in vases.

Though Ranunculus is not a type of plant that offers a cornucopia of varieties, the limited number that it does produce such perfectly-sculpted blooms that just about anyone with a flower garden will probably want to try their hand at Ranunculus!

Background & Origins

Genus Ranunculus girdles the globe – this cosmopolitan genus is absent from only a swath of land in western Africa, northern South America, and PNG.

Ranunculus asiaticus, the parent species for Garden Ranunculus, occurs in nature in a belt of land from Cyprus through Turkey and Iraq to Iran.

While the simple and cheery Ranunculus asiaticus, which occurs in colours from pale yellow to vermilion, are great for groundcover and wildflower gardens, the cultivars could not be more different.

Garden Ranunculus’s principal value, be they grown for floriculture or in-home gardens, is for cut flowers. Lasting for up to 10 days, they are mainstays in bridal bouquets and floral arrangements, and are attention-grabbers in vases in the living room.

Ranunculus grows from underground tubers which are, not quite accurately, also called corms.

Though the Persian Buttercup is native to several Eurasian countries, its centre of cultivation has been and is the United States. Garden Ranunculus is particularly popular in the southern states.

Varieties

Ranunculus plants have a bushy habit and often make a mounding form. The leaves are of a deep and rich green hue and are heavily lobed.

The lush but lacy, feathery foliage from which the flowers rise serves as a perfect nature-made backdrop for the blooms. The floral stems reach heights of 25 to 60 centimetres depending on the variety. 

The flowers come in white, and in yellow through orange to crimson and violet; the tones include pale pastels and rich saturated ones.

A few varieties bear gradated or edged –picotee – flowers. We run down our Top Ten, which will demonstrate the diversity of this plant’s floral palette and also introduce two or three series. All varieties produce fully double flowers.

‘Pot Dwarf Mix’ is from a series including many colours but its main feature is that at a mere 15 to 20 centimetres it is a dwarf variety that is meant to be grown in flower pots. The mix (of several tubers) will give you an abundance of colours in cheery hues of yellow, pink, orange, and red.

‘Tecolote White’ produces gauzy pure white blooms that are ideal for bridal bouquets. The Tecolote Series’ varieties are the basketball players among Ranunculus plans as the flower stems are 50 to 60 centimetres high.

‘Cloni Success Hanoi’ is an immensely popular hybrid-cultivar that will have you asking, “Is it white or is it pink?” as this sublime variety bears white flowers suffused with a gradated and uneven pinkish tinge or flush.

pale pink persian buttercup flowerheads
White, with the Demurest Flush of Pink – Ranunculus ‘Hanoi’

‘Purple Picotee’ notwithstanding its name is a white flower with virtually every petal edged, finely or thickly, with shades of purple ranging from pale pastel purple through cherry red to a deep purple.

‘Bloomingdale Pure Yellow’ is a wonder from the Bloomingdale Series which is the shorty in the family, reaching a height of 25 centimetres. These flowers are in intense hues of yellow varying from a sunny yellow to a golden yellow, and may even put up sulphur-yellow blooms.

‘Tecolote Pink’ bears blooms of a pastel pink to bright pink shade making them choice flowers for all kinds of bouquets. Though Tecolotes vary quite a bit in diameter, usually they are a good 10 centimetres across. 

‘Aviv Picotee Orange’ is a glorious flower has to be among the top picks from the Aviv Series which encompasses several colours. The blooms are in the richest hues of flame and orange, displaying subtle gradation and edging.

‘Tango’, another hybrid-cultivar, competes with roses, for its rich, fully double blooms come in shades of lipstick red through ‘rose red’ to ruby red. It is an automatic choice for Valentine’s Day bouquets.

‘Aviv Red’ blooms are as spectacular as any rose, for these double flowers occur in hues of intense red and crimson – the perfect flower for Valentine’s Day bouquets. It is one of the choice picks in the Aviv Series.

‘Bloomingdale Purple Shades’ produces such blooms that this variety should surely be used only as an accent plant – make that ’showstopper plant.’ The form of the flower is perhaps ideally suited for this variety’s hues which range from mid purple through crimson-purple to a dark, intense violet.

orange, red and pink Ranunculus Asiaticus growing in a Japanese Garden
Ranunculus Asiaticus Grown In A Japanese Garden

Habitat & Growing Conditions

Garden Ranunculus does not flourish in hot, humid conditions or in overly-damp soil. They grow best in well-draining light soils, and prefer climates that are temperate tending to cool.

At the same time, the tubers are not fully hardy and will not survive prolonged frosts.

The best type of climate for these plants is made up of mild winters, long springs with cooler temperatures, and pleasant summers that are not very warm or very rainy.

At a hardiness rating of Zone H4, Garden Ranunculus is just hardy enough for most of the United Kingdom.

Planting and growing Ranunculus in the UK is one of those fine-margin propositions such that your particular location will dictate your choices and will also strongly influence how successful you are in this endeavour.

Where to Plant Garden Ranunculus

Ranunculus offer at least three possibilities as to how best to deploy them in the garden. Preliminarily, though, these flowers are most suitable for courtyard gardens, city gardens, and even formal gardens. 

A mass planting of mixed varieties in a large bed will create a stunning effect in view of the form of the blooms and the colours. At the other extreme, a single plant of any of several varieties in a container will make a superlative accent plant for the entry steps. 

Finally, Ranunculus make excellent companion plants such that a few combinations are already established. Try yellow and orange Ranunculus varieties with traditional blue and purple Delphiniums, as just one example.

Rich Yellow Ranunculus Varieties – Excellent Companions for Delphiniums

Feeding, Care & Growing Tips

You can plant Garden Ranunculus tubers in two very different seasons so that they will, in turn, produce flowers in two very different seasons as well. In either case the flowering season will last for five weeks, stretching to six.

Autumn-planted tubers will put up flowering stems in March and spring-planted tubers will do so in June. Thus, if the summers in your particular region are not overly warm and humid, you can enjoy summer Ranunculus blooms, besides spring ones.

Aspect

In all parts of the United Kingdom except the balmiest ones these plants should be sited in full sun, otherwise they should get morning sun for about six hours.

Soil Requirements

A sand-based soil with little or no clay amended with organic compost or humus down to 7 to 8 centimetres will suit these plants very well.

Soil pH should be in the Slightly Acidic to Neutral range – 6.1 to 7.3 – or thereabouts. 

The soil should drain very well as this plant’s tubers are at risk of rotting in damp or poorly-drained soil.

If you need to enhance drainage incorporate gravel at the bottom layer or mix in perlite. You can also facilitate drainage by forming ridges or mounds into which to plant the tubers. 

Apart from the garden, Ranunculus tubers may also be planted in suitably-sized containers.

mass planting of ranunculus tecolote at a commercial growing site
A Mass Planting of Tall Ranunculus Tecolote at a Commercial Site

Tubers

Commercial-class Ranunculus tubers are sold in four grades, from Jumbo, the largest, down to Number Three.

Jumbos are about 2.5 centimetres wide with the other grades being progressively smaller. (The classification and nomenclature used here are American. Dutch bulb merchants and growers classify and name tubers somewhat differently.)

If you intend to grow Ranunculus in a sizeable bed, you can go with a large number of smaller, less floriferous, and certainly less expensive Number Two tubers.

For container-growing and for specimen plants, you should buy Jumbos. No matter which ones you get, tubers should be dry, firm, and without any nick or blemish.

Planting

Before planting the tubers, you may soak them in water at room temperature for an hour or two but no more.  

In regions in Zone 3 or warmer, you can plant tubers in November, early spring, or both, otherwise plant them after the last frost. However, note that the tubers need temperatures of 9° to 13° centigrade to germinate.

If average temperature is not within this range then you will need to germinate the tuber indoors or under glass in controlled conditions.

Tubers should be planted about 4 centimetres deep. Jumbos should be spaced about 25 centimetres apart; Number Twos about 13 centimetres apart.

A Mass Planting of Ranunculus Bloomingdale in various strips of colour
A Mass Planting of Colourful Ranunculus Bloomingdale at a Commercial Site

They must be planted with the ‘claws,’ from which the roots will grow, downward. Backfill the hole and gently firm up the soil.

Watering

Water well after planting. You may apply a thin mulch of hay, straw, or bark.

Water twice or three times per week. The soil should not become waterlogged nor should it be allowed to completely dry out in the initial growing phase. It should be kept just moist.

Decrease the quantity and frequency of watering after the plants become established, and cease watering after they have shed their leaves and become dormant.

Fertilising

In the beginning of spring or at the end of spring, depending on when you planted the tubers, feed the plants with a 5-10-10 slow-release fertiliser. Alternatively, mix in bonemeal into the soil several centimetres away from the tubers.

Overwintering

Though Ranunculus will grow outdoors in most regions of the United Kingdom, whether or not you should lift the tubers for the winter depends on your precise location, the possibility of a hard frost, and the kind of soil you have prepared.

If you live in a region of Hardiness Zone 5 or colder, if you anticipate an extended frost, if your soil does not drain very well, or if you anticipate a wet summer, you should remove the tubers for indoor storage until planting season comes around, otherwise simply dispose of them and buy new tubers the following season.

You can circumvent the need to remove tubers and re-plant them by growing Ranunculus in appropriately-sized containers.

If you need to lift your tubers, cut off the tops, allow them to dry out in a cool, dry, dark room, and store them in a similar environment, after lightly packing them in peat moss and putting them in a mesh bag.

Pruning Guidelines

If you want to cut flowers for indoor display, do so just after the buds have coloured and are beginning to open. Flowers cut during the morning hours will last longer.

Promptly deadhead spent flowers so as to stimulate fresh blooms.

Do not prune yellowing, wilting leaves as they continue to supply energy to the tubers, and thus replenish their stores for the season to come.

Remove leaves only after they have died at the season’s end. 

mixed persian buttercup flowers in a glass vase placed in a living room
Mixed Ranunculus Flowers in a Vase in the Living Room

Garden Ranunculus is Poisonous

Though Garden Ranunculus is not quite as poisonous as many Ranunculus species, it is still a poisonous plant. Both flowers and foliage are poisonous to humans and animals alike.

Symptoms of Ranunculus poisoning include, among others, hypersalivation, oral blistering, abdominal pain, diarrhoea, and vomiting.

Any person or pet suspected of suffering from Ranunculus poisoning should receive immediate medical attention.

Common Diseases & Problems

Belying their delicate and refined appearance, Ranunculus are relatively healthy plants that do not suffer from many pests or diseases. All you need to watch out for are aphids and powdery mildew.

Aphids can be combated with organic remedies such as BotaniGard ES or Safer’s soap. Apply these products per the instructions on the packaging. 

If you see powdery mildew on a plant cut off the affected parts and promptly remove them from the garden.

Ensure that the plant is getting sufficient sun and is not closed-in by other plants. You can avoid mildews by watering at soil level so that foliage does not get damp.

Where to Buy Garden Ranunculus

You can buy Garden Ranunculus as potted plants and as tubers.

a golden persian buttercup flower in focus
Golden Persian Buttercup Flower

During the spring flowering season you may be able to find a few varieties as potted plants at the more well-stocked nurseries.

You can get tubers from merchants who specialise in bulbs and seeds, be it from online stores or brick-and-mortar ones.

They may not be very easy to find online at British sites and you will probably have better luck sourcing them from American bulb merchants which sell quite a variety of Garden Ranunculus tubers.

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