Many gardeners love growing Ranunculus [ra-NUN-ku-lus] (Ranunculus asiaticus) with its beautiful flowers in a wide variety of gorgeous colors.
Their blossoms look like works of art with their layers of crepe paper thin petals.
Ranunculus plants do best in the southern and western United States, but with attentive care, can also be grown in slightly cool weather climates.
In this article, we describe Ranunculus and share proper care of these exotic and irresistible garden plants. Read on to learn more.
Ranunculus Care & Profile
The name, Ranunculus Asiaticus comes from the Latin:
- “rana” meaning frog, and these plants are so called because many wild species do grow in damp settings.
- Asiaticus refers to the place from which many species hail, Asia.
Ranunculus belongs to the buttercup family, and this explains some of its common names:
- Persian Buttercups
- Crow’s Foot – because of its claw-like tubers
Plant Type: Perennial (Tuber, Corm or Bulb)
Native: North Africa, Southwest Asia and Southern Europe
USDA Hardiness Zones: 8 – 10
Height & Spread: 1′ to 2′ feet
Bloom Time: May through June depending upon climate.
Flowers: Showy and brightly colored in many primary, pastel and combined shades.
Light: Full Sun
Soil: Light, airy and well-draining
Fertilizer: Bonemeal and bulb fertilizer at the time of planting. Balanced water-soluble fertilizer at end of the season if overwintering bulbs outdoors.
Suggested Best Use: Annual for containers, borders and flower beds.
Ranunculus Culture & Environment
The Ranunculus plant is extremely prone to tuber rot. The soil must be very well drained and light. The pots of potted Ranunculus must have drainage holes.
A slightly elevated setting is preferred. Ranunculus need cooler temperatures and full sun simultaneously.
If you grow in an area with very cold winters and hot summers, the timing of planting is extremely important.
Be sure to avoid both excesses and cold and heat because very hot weather discourages these cool-season flowers from blooming.
What Do Ranunculus Look Like?
The strong stems and leaves of these Ranunculus bulbs look a little bit like celery plants.
Depending upon the species, buttercup flowers an grow to be a foot-high to 18″ inches high in mounds measuring 6″ to 12″ inches across. There are some smaller Ranunculus asiaticus varieties that top out at about 10″ inches high.
The beautiful blooms may be 3″ to 6″ inches across. The Persian buttercup begins to bloom early in the spring garden and continues blooming until mid-summer. When Ranunculus bloom they come in a wide range of colors including:
- White – Ranunculus asiaticus
- Rose Tecolote® Ranunculus
- French Pink Ranunculus
- Red – Tecolote Red Ranunculus
… and a wide variety of pastel colors.
Where Can You Grow Ranunculus?
These plants are cool season perennials, hardy in USDA zones 8-10. They do well in areas where the winter is mild and the springtime is lengthy and cool.
For this reason, they are very popular in the southern and western United States (e.g. Louisiana, Texas, New Mexico, Arizona, Nevada and California).
In these areas, you can plant the claw-like bulbs in October and expect a wealth of flowers in March.
How To Choose The Best Ranunculus Bulbs?
Ranunculus tubers are available in four different sizes or grades. They are:
Jumbo tubers: these are 2″-4” around. This size bulb will produce about 35 flowers.
#1 Size Tubers: a little bit smaller, 2.25″ – 2.75″ inches around. This size bulb will produce about 20 flowers.
#2 Size Tubers: is smaller still at 2″ – 2.25″ inches around. This size bulb produces about a dozen flowers.
#3 Size Tubers: are quite small, a little over an inch but no larger than 2.25″ inches around. This size bulb produces about seven flowers.
Jumbo bulbs and #1 size are best for container planting, produce a larger number of flowers and also better for planting small areas. If you’re doing mass plantings, the #2 and #3 size are fine.
If you just want a plant or two, you can look for Ranunculus already potted at your local nursery.
When Do You Plant Ranunculus?
Your timing for outdoor planting depends upon your location. In areas with very mild winters, fall planting will produce spring blooms.
In colder areas (zone 7 and farther north) plant early in the spring, just before the final frost. Expect blossoms during the months of June and July.
Alternately, plant Ranunculus tubers indoors during the month of February and then transplant them outdoors after all danger of frost passes. These plants should also bloom during the months of June and July.
How To Plant Ranunculus Tubers?
When purchasing Ranunculus the tubers will be hard and dry. Some gardeners like to soak the tubers before planting, but there is some risk in doing this.
If the tubers stay wet for too long they will rot and not grow at all. It’s actually all right to plant them as-is. They will soak up water from the surrounding soil and grow just fine.
You should be certain that the soil surrounding them is not soggy. Ranunculus do best in airy, well-drained soil.
They like a bright, location with lots of sun. They do not do well in a warm, wet setting.
6 Steps to Planting Ranunculus Outdoors
#1 – Choose a slightly elevated, well-drained location that receives at least 5 to 6 hours of sunlight daily. The site should have light, airy soil with a neutral pH level (pH 6 to 7).
If your soil tends to be clay-like, it will need to be amended or establish a raised bed as these plants will not do well with poor drainage.
#2 – Before planting your bulbs it’s a good idea to spread bonemeal and bulb fertilizer over the planting area.
Follow packaging instructions for the bonemeal, but use only half as much fertilizer as instructed by the manufacturer. Add one or 2″ inches of organic matter (e.g. compost).
#3 – Turn the soil thoroughly to a depth of 9″-12″ inches. Work all of the soil amendments in thoroughly.
#4 – Water thoroughly before planting the tubers and wait 24 hours.
#5 – When planting Ranunculus tubers, dig holes or trenches an inch or two deep, and be sure that the claws are pointing down.
Give the tubers plenty of room to grow and spread. Place Jumbo tubers about 8″ to 12″ inches apart. #3 tubers can be planted about 4″ inches apart.
#6 – Once you have the tubers in place, cover them with soil and mulch fairly heavily using straw, coco hulls or bark.
This will help the soil retain moisture. Do not water again until the tubers sprout.
How to Grow Ranunculus From Seed
Another way to start Ranunculus is to grow them from seed indoors in late winter.
Ranunculus seeds are tiny and should be sown on the surface of a very light, with a peat moss base, sterile seed starting mix.
Be advised that the percentage of seeds that will actually sprout is rather small, so you’ll want to sow the seed quite heavily.
Once Ranunculus seeds are soon, place the seedling tray in a bright, airy place with a consistent temperature of about 50° degrees Fahrenheit.
Seedlings should germinate within 20 or 30 days. Once this happens, increase the temperature to about 55° degrees Fahrenheit. Plant Ranunculus outdoors after all danger of frost has passed and expect flowers in June.
When growing Ranunculus in pots or container, be sure there’s plenty of room for the roots to grow.
Ranunculus have very extensive root systems, and need a minimum of a 10″ inch pot for one or two jumbo size tubers or three #2 tubers.
Steps to Caring for Ranunculus
#1 – When your tubers sprout, give them a moderate watering. Don’t overdo it because the tubers do tend to rot easily.
#2 – Deadhead spent flowers throughout Ranunculus flowering season to encourage more blossoms.
#3 – When blooming stops and foliage begins to die back, stop watering.
#4 – If you live in an area where the tubers can overwinter in the ground, apply a light feeding of a balanced, water-soluble fertilizer (10 – 10 – 10).
Alternately, use a fertilizer blend formulated especially for bulbs or sprinkle the whole area with bonemeal.
#5 – Provide a light, final watering before winter.
How Do You Care for Ranunculus Flowers?
As with most flowering plants, frequent deadheading encourages more blooming.
Persian buttercups flowers are wonderful cut flowers, and have a long vase life so cutting bouquets frequently is a good idea. Kept in clean water, a Ranunculus bouquet will last about a week.
What To When The Buttercup Flowers Stop Blooming?
If you have the perfect climate and the perfect soil, leave your Ranunculus tubers in the ground. “Buttercups” will overwinter and come up happily the next spring.
If you don’t live in an area that has mild winters, you may wish to take up your tubers and store them in a cool, dark, dry place throughout the winter.
For most people, this is too much trouble, and the chances of bulb survival are actually fairly low.
Persian buttercup tubers are inexpensive, and it is generally thought easier and smarter to just leave them where they are and start over with new plants the next season.
How To Store Ranunculus Bulbs
If you want to try to save the Persian buttercup bulbs or tubers from one season to the next, dig them up and store them until the springtime.
After digging them up, cut off the tops or leave them on. Shake off excess dirt and lay the bulbs out in a warm, airy place to dry for a week or two.
Once the bulbs are completely dry, pack them lightly in a dry, airy material such as vermiculite.
Alternately, put them in cloth or net bags and hang them up in a well ventilated, dark area. Keep them cool and dry at temperatures ranging from 60° to 68° degrees Fahrenheit.
Are Ranunculus Poisonous?
All parts of Ranunculus plants are considered poisonous. Contact may cause negative reactions through both ingestion or simply through contact.
Ingestion of any part of the plant can cause symptoms including:
- Burning Sensations in the Mouth
- Bloody Diarrhea
- Abdominal Pain
Contact with the plant can cause symptoms including:
- Burning Sensations
It is important to note that Ranunculus is only toxic if:
- Large amounts are eaten
- The skin is closely exposed to open Ranunculus plant for an extended period of time.
Even so, it’s a good idea to keep pets and children away from the plant and to wash up thoroughly after handling the bulbs, foliage and/or flowers.