All About Ranunculus – Detailed Buttercup Growing & Care Guide

Dubbed “the rose of the spring” by florists and admirers of beauty alike, Ranunculus has gorgeous, double-petaled blooms. With shades ranging from the softest pastels to the deepest midnight purples, they’re a favorite in bouquets and wedding arrangements.

Ranunculus, also known as the Persian Buttercup, is a popular ornamental plant for a reason. With its plentiful foliage and showy flowers, planting it in your cut garden or even a container is a huge treat.

Here’s a detailed Ranunculus growing & care guide that will teach you all about Ranunculus. You’ll also learn how to have a bountiful, beautiful yield of these eye-catching flowers.

Two red ranunculus flowers with blooming buds and foliage

What Are Ranunculus Flowers?

Shaped like a tenfold rose, with lush petals that form a round, flattened bloom, Ranunculus asiaticus is a sight to behold.

You wouldn’t believe that before breeding these traits, Persian buttercups were single-petaled wildflowers that naturally grew in the Eastern Mediterranean basin.

After modifying Ranunculus cultivars, their popularity skyrocketed. They now have many gorgeous shades that include pastels (Hanoi, Rhone Pink, Marshmallow), vibrant yellows and oranges (Flamenco, Elegance Orange), and deep, dark varieties (Trenton Black, Burgundy Wine).

Ranunculus is a staple in bridal bouquets and floral arrangements. They’re also scentless, so they make for awesome dinner table centerpieces and won’t bother anyone with a sensitive nose.

They don’t require pesticides like roses do and have pretty simple growing conditions. So, read on to know more about how to grow and care for these beauties.

How to Grow Ranunculus

Ranunculus can be grown from corms or seeds. We’ll go into detail about each method as well as the pros and cons of growing your buttercups either way.

How to Grow Ranunculus From Corms

Corms, sometimes called bulbs, are octopus-shaped, dried parts of the Ranunculus plant. When planted in the soil, the corms start to sprout roots and shoots that grow into a full plant.

Step 1: Choosing the Corms

To achieve the desired Ranunculus yield, you should set yourself up for success by choosing the biggest, most robust corms you can find. 

Corms serve as an energy storage organ during the first few weeks of the plant’s life. The bigger its size, the more food it has to offer the young plant. As a result, a plant’s flowers and foliage that grow from a bigger corm become larger and stronger.

Shoot for corms that come with a “No. 1” label, which are about 6–7 cm. They’re slightly more expensive, but their brilliant blooms more than make up for the price.

For large-scale flower farming, corms are usually ordered in the spring and arrive by the fall. Then, they’re planted in the spring of the following year. So, it’s best to be prepared with a list of the varieties you want to plant ahead of time.

Step 2: Soaking the Corms

When you first get the corms, they’re relatively small in size. You need to soak them to bring them back to life and boost your chances of successfully growing Ranunculus from them.

Depending on the number of corms you have, choose an appropriately-sized bucket or container, fill it up with water, and place your corms in it.

To prevent bacterial buildup, you should keep the water agitated. You can do this by using either a fish tank filter or a trickle of fresh water from a tap.

Many people place the corms inside a mesh bag for easy retrieval, which allows them to drain the corms without handling them too much. 

Leave the corms in the water for a maximum of four hours. When they’re done soaking, the corms should plump up and almost double in size.

Make sure not to over-soak your corms as they can disintegrate if they absorb too much water. There’s also a higher chance they’ll rot once they’re put in the sprouting medium if they soak for too long.

Step 3: Pre-sprouting the Corms

This step is optional but highly recommended. After your corms are done soaking, prepare a flat tray with about an inch of damp seed-growing mix. You can opt for a pre-made mix, but you can also make your own out of the following:

You can use 72-plug trays, but the growing roots can intermingle and be more difficult to separate. Beware of damaging the Ranunculus seedlings when you transplant them as they’re very fragile.

Steps of Pre-sprouting the Corms
  • Once you’ve placed the growing mix, place the corms claw side down in the tray, about one inch apart. Cover with another inch of loosely packed growing mix, and set aside.
  • Choose a relatively dry, cool spot to place the trays, about 55–60℉ with minimal humidity. The sprouts need about 6 hours of light per day, but avoid direct sunlight at this stage.
  • You can enrich the growing mix with a slow-releasing fertilizer. Just choose one that’s not nitrogen-heavy because it can make for a very leafy plant without any flowers.

This stage can last anywhere between 4–6 weeks, after which you can transplant the sprouts to a container, a garden border, or a greenhouse (hoop).

If you live in hardiness zones 7–11, you can start the pre-sprouting in late January. For zones cooler than zone 7, it’s better to start in mid-to-late February.

Transplanting the seedlings should happen only when there’s no danger of frost and the ground has completely thawed.

Image of yellow-orange ranunculus bouquet on white background.

Step 4: Transplanting the Seedlings

Once the Ranunculus corms have sprouted into healthy seedlings with at least 4 true leaves, it’s time to separate and transplant. You can place them directly into your garden soil or the container you’ll keep them in.

Plant them in well-tilled, compost-enriched soil in your garden or soilless potting mix in a container. Ranunculus requires well-draining, sandy or loamy soil that’s slightly acidic. 

If you’re planting in a flowerpot, place some gravel at the bottom of the container to aid with drainage and prevent the soil from caking.

Place the seedlings 4–6 inches apart to allow their roots to spread laterally. If you place them too close together, they can become rootbound, which limits their growth and blooming.

As soon as you’re done transplanting all of your seedlings, water the soil, not the plant. Ranunculus likes barely moist soil, and overwatering can rot and kill the roots. 

Use slow-releasing fertilizer every 15 to 18 days to aid with flowering. Just make a hole in the soil to the side of the root, place the granules in it, and water immediately after.

You can expect the first buds to form about two months after sprouting the corms. Then, less than two weeks later, Ranunculus flowers should bloom.

How to Grow Ranunculus From Seeds

Ranunculus seeds are very small and thin. They resemble coarse chili pepper flakes but are a beige/brownish color. 

If you choose to go the seed route, you should know that they have a low germination rate. Other than that, growing them is very similar to planting corms.

Step 1: Choosing the Seeds

Just like with corms, you should get your Ranunculus seeds from a trusted source. Aim for a high-quality, preferably local vendor with a good reputation. 

Unlike corms, which can only be ordered for a few months ahead of time, seeds are mostly available year-round. 

If you want certain color groups, avoid seed mixes that are too widely varied. However, if you’re still starting out, try any mix you prefer. This way you’ll know how each color grows and what it responds to.

Step 2: Sowing the Seeds

You should plant Ranunculus from seed between September and December, as they fare better during the cooler months.

Start with a flat, wide tray and a couple of inches of soilless growing mix for your seeds. Since Ranunculus germination rate is quite low, you should sprinkle on a large number of seeds.

After you sow the seeds, cover them with a generous sprinkling of the growing mix. The rule of thumb is that the amount of soil should be approximately two to three times the width of the seeds.

Then, use a flat object to flatten the soil and ensure good seed-to-soil contact.

Generously water the growing mix, but avoid using a hose or you’ll wash away the smaller seeds. Afterward, you can place the tray in a spot that gets ample sunlight to aid with its growth and prevent weak stems.

The seeds usually start to germinate after 12–15 days, but true leaves won’t appear until 45 days have passed. During this period, it’s important to monitor the water content of the soil so it doesn’t get too dry, which can prevent the seeds from thriving.

Once you have at least four true leaves, or after 65 days of sowing the seeds, you’re ready to transplant them into your container or garden.

Step 3: Transplanting the Seedlings

This step is exactly like transplanting the plants grown from corms. In this case, you should be extra careful when separating the seedling roots, as they’re thinner and more fragile at this stage.

To aid with growth and flowering, you can use a water-soluble fertilizer added to a spray bottle and spray the plant every 18–20 days. A balanced fertilizer will give you stronger plants and more robust blooms.

You can expect grown Ranunculus blooms from seeds after about 90–100 days of sowing the seeds. If you start the process in December, the flowers will blossom by March.

Image of orange, persian flower buttercup ranunculus

How to Care for Ranunculus?

Ranunculus is a relatively low-maintenance flowering plant. If you provide it with ample sunlight, frequent watering, and slow-releasing fertilizer, you’ll get beautiful blooms that’ll last anywhere between four and seven weeks.

Ranunculus prefers the cool, crisp spring weather and thrives when the ambient temperature is about 55℉. It likes full sunlight for about six hours every day. 

However, if you live in the warmer hardiness zones, make sure to provide it with shade during the hottest hours of the day. This will protect the leaves so they don’t get burnt.

Ranunculus prefers well-draining, sandy or loamy soil. Packed clay soil can retain stagnant moisture, which is the perfect environment for plant diseases like root rot.

Water your Ranunculus sparingly but frequently, about one inch per week. If you live somewhere hot and dry, you can increase the watering frequency a bit more.

You can also cover the soil with mulch, like straw, bark, or coco coir to reduce the rate of evaporation.

To get beautiful blooms that last, fertilize the soil every 2–3 weeks using a slow-release fertilizer. Avoid fertilizers that are heavy in nitrogen, as they’ll promote foliage growth but inhibit flowering.

How to Propagate Ranunculus?

Ranunculus can be propagated by corms or seeds. If you find a variety you like, you can wait till the plant is fully grown and has died back in the fall to divide the corms

Most of the corms will have new growths (called offsets) attached to them. Use a sharp knife to separate them from the corms. For those who live in hardiness zones 8–10, go ahead and plant them right away.

If you live in cooler hardiness zones, you’ll have to overwinter your corms to plant them next year. We’ll go into detail about this process down below.

To propagate from seeds, follow these steps:

  • Once the Ranunculus blooms have faded, deadhead them to allow the plant to produce new blooms. 
  • Save the spent flowers and collect seeds from them.
  • Dry the flowers out for a couple of days in a cool, dark spot. 
  • Place them in a paper bag, shake vigorously, and the seeds should fall out. Be careful when you open the bag, because Ranunculus seeds are small, light, and can very easily fly away.

Once the weather allows for seed planting, follow the steps mentioned above to grow Ranunculus from seeds.

How to Overwinter Ranunculus?

Overwintering is the process of protecting the bulbs or corms of a plant from the lowest temperatures during fall and winter to be planted the following year.

Ranunculus are perennial in hardiness zones 8–10. If you live anywhere cooler, you’ll have to take the corms out of the soil before the first frost hits.

After the plant dies back in the fall, stop watering it, trim the yellow leaves to the level of the soil, and then take the corms out. Remove excess soil and longer root tendrils that have completely dried out.

Don’t delay this step as some small animals, like voles, can dig out and eat the corms if they remain in the soil for too long. There’s also the danger of frost killing them off before you can overwinter them.

Take the corms and place them in a cool, dry place for a couple of days, then transfer them to a dry medium such as peat moss.

Place them in a box or paper bag until you’re ready to plant them the following year. Just check on them every now and then to make sure they’re not rotting.

Keep in mind that this process doesn’t always succeed and some corm failure is expected. This is why most people in hardiness zones 4–7 treat Ranunculus as an annual plant and prefer to purchase new corms every spring.

Closeup of a ranunculus with the petals starting to fall off.

What Are the Diseases and Pests That Affect Ranunculus?

Even the best cared-for plants can fall victim to pests and diseases that stunt growth and affect flowering. Thanks to its showy flowers, Ranunculus can attract several pests that can be detrimental to its health and growth.

Here’s a rundown of the most common diseases and pests that can affect your Ranunculus:

Powdery Mildew

This disease affects the Ranunculus plant and shows in the shape of gray, pinkish, or whitish dust on the leaves. It’s usually the result of poor air circulation.

You can treat powdery mildew by cutting off the affected leaves and stems with disinfected pruning shears. It’s advisable to keep monitoring the plant for the following weeks to make sure the mildew doesn’t return.

Root Rot

This disease is a fungal infection that affects the root of the Ranunculus plant. It’s mainly caused by overwatering and inadequate soil drainage.

It can cause droopy leaves and stems. An unpleasant odor from the plant may develop if the infection goes on without intervention.

Unfortunately, plants affected by root rot can’t be saved, but you can prevent its spread to neighboring plants. Remove the affected plant as well as the soil it’s been planted in and discard them. 

If the Ranunculus was planted inside a container, clean the container thoroughly and treat it with a fungicide before using it for another plant.

Aphids

Aphids are tiny, green insects that mainly feed on tree sap. They’re mostly harmless. However, if the infestation is severe enough, the plant becomes lifeless and droopy, and the edges of the leaves become pale and dry.

You can protect your Ranunculus (and other plants) from aphids by spraying it with watered-down dish soap mixed with alcohol, essential oils, or both. This makes the plant sap taste worse for the aphids and drives them away.

Mealybugs

These tiny bugs appear in a snow-like coating on the leaves and can be devastating to a plant. They feed on sap, just like aphids, and can draw the life out of the plant very fast.

Mealybugs cause wilting, drooping, and stunted growth. They can spread fast from one plant to another, causing a crisis for your garden.

Fortunately, you can save your plant by wiping the visible infestation points with a cotton ball dipped in alcohol. Then, you can use a watered-down dish soap and alcohol spray to drive the mealybugs away and prevent further deterioration.

Birds, Squirrels, and Voles

Depending on where you live, wildlife can greatly affect your Ranunculus yield. Birds can feast on the tender shoots of your seedlings and enough of them can irreversibly ruin your plants. 

Squirrels and voles, on the other hand, can dig up and eat the corms when you first plant them as well as after the plant dies back in the fall. This situation can be especially annoying if you plan to overwinter your corms for the following year.

There are a couple of ways you can mitigate the problems that arise from wildlife. You can cover your growing plants with special netting, which prevents the birds from getting to them before they’re six inches high. You can uncover the plants after, as they’ll have grown strong enough to withstand avian attacks.

You can also try to feed the animals in an area away from your plants. This way they’ll keep their hands off of the Ranunculus. 

Frequently Asked Questions

Here are a few questions that readers have about Ranunculus: 

Are Ranunculus and peonies the same?

Ranunculus and peonies aren’t the same plants and don’t belong to the same plant family.

Appearance-wise, they’re very similar, though peonies are smaller and rounder than Ranunculus blooms. They do, however, work well together in floral arrangements!

How long do Ranunculus flowers last?

In the garden, you can enjoy Ranunculus blooms for 4–7 weeks, depending on your hardiness zone and when the flowers were planted. As cut flowers, Ranunculus has a long-lasting life of about two weeks in the vase.

If you plan on keeping Ranunculus in the vase, you should cut the flowers before they fully bloom. They will continue to blossom if cared for properly and will almost reach their full size.

How do you keep Ranunculus blooming?

You can prolong Ranunculus blooming by providing the plants with enough shade during the hottest hours of the day. You should also keep them in an area with adequate air circulation and spray them with a high-phosphorus fertilizer every two to three weeks.

To encourage the plant to produce more flowers, deadhead the spent blooms as soon as they fade. You’ll soon find a new bud has appeared and blossomed after you cut the dead parts of the plant.

Conclusion

Growing and caring for Ranunculus plants is a very rewarding experience. All it takes to grow these magnificent flowers is some basic gardening knowledge, a few tools, and some vigilance to the wellbeing of your plant.

The factors to keep an eye out for while caring for your Ranunculus are soil moisture, sun exposure, and pest control.

Whether you’re growing them for personal enjoyment or planning on growing them commercially, Ranunculus will bring beauty to your life. 

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