Ranunculus Growing Guide: From Corm to Vase
The echoes of spring days are fading, and with them go some of the garden’s most enchanting blooms. This year’s cold spring allowed a few cool-loving flowers to linger, but as the summer solstice arrives, one standout cultivar bids us farewell until next season.
I admit, letting go of ranunculus is never easy. They are the epitome of spring beauty, versatile and captivating. While I await the arrival of dahlias to fill the void, the ranunculus holds a special place in my heart—a friend I both adore and begrudgingly part with.
Often called the “rose of spring,” ranunculus are as fickle as they are breathtaking. These beauties demand just the right conditions—earning their nickname as the Goldilocks of flowers—but the reward for your effort is armloads of dreamy blooms that will make your heart sing.
Whether you’re new to growing ranunculus or looking to refine your techniques, this guide will help you navigate their unique quirks and maximize your spring harvest. And for a quick rundown, check out the 5-Minute Flower Friday video linked at the end of this post!
Note: This post contains affiliate links. If you make a purchase through these links, I may earn a small commission at no additional cost to you. Thank you for supporting our farm!
Where, What, and Why: Buying Ranunculus Corms
What Are Ranunculus Corms?
Ranunculus grow from corms, which are similar to tubers. Each corm produces plants with the same traits as the mother plant—color, flower form, size, and stem length all depend on the variety you choose.
When to Buy Ranunculus Corms
Most commercial growers place their orders in winter or spring for fall shipping, meaning they’re ordering a year or more before blooms appear. Smaller-scale growers or home gardeners may find corms available in the fall from garden retailers closer to planting time.
Pro Tip: If you’re new to growing ranunculus, starting small with a few corms from a trusted garden retailer is a great way to learn.
Where to Buy Ranunculus Corms
In my first season, I picked up clearance corms from Costco. While they were affordable, the results were underwhelming compared to what I achieved with higher-quality corms from reputable wholesalers. Premium corms consistently produce healthier plants with longer stems and larger blooms.
For larger-scale planting, wholesale suppliers are the way to go. Look for trusted suppliers that specialize in ranunculus and offer a wide variety of colors, forms, and corm sizes.
If you’re ordering corms for fall shipping but don’t plan to plant until late winter or early spring, store them in a cool, dry place to keep them dormant.
Pro Tip: Start your search early to secure your favorite ranunculus varieties and sizes, especially if ordering for fall shipping.
Harvesting Cloni Ranunculus Nuance at sunset, a moment of beauty amidst a thriving spring patch
Which Ranunculus Varieties to Choose?
Ranunculus varieties come in a stunning array of colors and forms, making them a must-have for any flower farm. When selecting varieties, I focus on their performance as cut flowers and the color trends most requested by clients.
For cut flower production, look for varieties known for:
Strong, long stems to make harvesting and arranging easier.
High petal counts for full, lush blooms.
Good vase life to ensure customer satisfaction.
Popular Colors and Trends:
Soft pastels like blush, peach, and ivory are wedding favorites, while bold tones like burgundy and coral are perfect for vibrant market bouquets. Keeping an eye on color trends ensures I’m always growing what customers want most.
Specialty Varieties to Explore:
While the Elegance series remains one of my go-to choices for reliability and affordability, I also experiment with premium varieties like the Cloni series for their lush, full forms and Japanese Butterfly ranunculus for their delicate, fluttery petals. These specialty types can elevate arrangements and appeal to high-end markets.
Plan for Seasonality:
Consider your bloom timing when choosing varieties. Some perform better in cooler, early spring conditions, while others thrive as temperatures begin to warm. Knowing your season’s demands can help you plan accordingly.
Experimenting with New Varieties:
Every year, I dedicate a small section of my field to test new or experimental varieties. It’s a great way to diversify offerings and stay ahead of trends without overcommitting to unproven options.
By selecting varieties with great vase life, sturdy stems, and popular colors, you’ll ensure your ranunculus not only thrive in the field but also delight customers and elevate your designs.
Deciding on What Size Ranunculus Corms to Purchase
Wait... size?! Yes, ranunculus corms come in different sizes, much like anemones, and the size you choose can impact your plant’s performance.
Understanding Corm Sizes:
Corms are measured in centimeters, with common sizes including:
2/3 cm
3/4 cm
4/5 cm
5/7 cm
The larger the corm, the higher the price, which can make smaller sizes more tempting. However, larger corms often produce stronger plants with more robust blooms, making them a worthwhile investment, especially in challenging climates.
My Recommendation:
I don’t go smaller than 3/4 cm, and for my high-altitude, high-desert climate, I often opt for the largest sizes. The additional cost is worth it for healthier plants that can handle our erratic weather—frost one day, 90°F the next!
If you live in a milder climate, smaller corms may perform well for you. But for those in harsher conditions, I recommend investing in larger corms to give your plants the best chance to thrive.
Dried ranunculus corms ready for soaking and planting.
What Ranunculus Corms Look Like Upon Receiving
When your ranunculus corms arrive, you might be surprised—they look a bit like dried-up baby squid or calamari! Shipped in a dormant state, these corms are hard, shriveled, and not exactly what you’d expect to grow into lush, beautiful blooms.
The First Step: Waking Up Your Corms
To bring your corms out of dormancy, they need to be rehydrated. This involves soaking them in room-temperature water for 3–4 hours. Proper pre-soaking is crucial for plumping up the corms and preparing them for planting.
For a detailed guide on how to pre-soak your ranunculus corms to ensure success, check out our blog on pre-soaking corms.
Choose Your Adventure: Planting or Pre-Sprouting
After soaking, you can either plant the corms directly into prepared garden beds or take the extra step of pre-sprouting them. Pre-sprouting is especially beneficial for ranunculus, as it helps jumpstart growth and reduces the risk of corm rot.
For step-by-step instructions on pre-sprouting ranunculus corms, visit our pre-sprouting blog.
A pastel bouquet of Dolce Vita ranunculus, freshly harvested and perfect for spring designs.
When Can I Expect to Have Ranunculus Once I Wake Up the Corms?
Once you break dormancy by soaking your corms, the countdown to blooms begins. Under optimal growing conditions, you can expect your first ranunculus bloom in about 90 days.
Timing Your Blooms:
In warmer climates, ranunculus can bloom as early as late winter through spring.
In colder climates, blooms typically appear from spring to early summer.
Several factors can influence this timeline, including:
Planting Method: Pre-sprouting corms often leads to earlier and more robust blooms.
Climate: Warmer temperatures can speed up growth, while cooler climates may delay it.
Growing Conditions: Adequate light, consistent watering, and good soil drainage are key.
Infrastructure Matters:
Ranunculus are sensitive to extreme temperatures—they dislike freezing conditions as much as they do prolonged heat above 70°F. To keep your plants on track, consider using low tunnels, double low tunnels, or high tunnels to protect them from weather extremes.
For high-quality materials, check out:
For tips on using season extension methods to protect your plants and extend their growing period, check out our season extension guide.
When to Plant Out Ranunculus
Ranunculus thrive when planted in soil temperatures of about 50°F, but timing your planting depends on your climate and setup. These plants can’t tolerate freezing, soggy conditions, so planning carefully is key to success.
Fall Planting
Ranunculus can overwinter in zones 7 and warmer with proper care. The key to fall planting is to ensure they are well-established before cold weather sets in.
Protect from Winter Stress: Even in warmer climates, wind, rain, and snow can weaken plants, making them more susceptible to disease. Using low tunnels or frost covers helps keep them cozy and productive.
Ideal Timing: Plant in the early fall when soil and air temperatures are still warm enough for root development.
Late Winter/Early Spring Planting
For many growers, planting ranunculus in late winter or early spring is more practical.
Timing for Blooms: This approach aligns bloom timing with popular markets like spring weddings or Mother’s Day.
Practical Tips: Plant corms in March through April under low or double tunnels to protect them from temperature swings. This strategy ensures blooms from May through late June in colder climates.
Curious about the best time to plant? Check out our blog on When to Plant Out: Frost Dates, Soil Temps, and Timing for a detailed guide to get your ranunculus timing just right.
Infrastructure for Success
Ranunculus benefit greatly from structures like low tunnels or micro tunnels, which help protect them from freezing temperatures and excessive rain. Additionally, having shade cloth on hand is a smart strategy for sudden spikes in heat, as ranunculus struggle in temperatures above 70°F. These setups provide a stable environment, improving plant health and bloom quality.
Pro Tip: Keep a close eye on weather patterns and soil conditions to avoid planting in overly cold or wet soil, which can lead to rot.
Need reliable solutions for weather protection? Check out shade cloth and low tunnel kits to shield your ranunculus from temperature extremes and ensure healthy, high-quality blooms.
Planting Ranunculus
Yay! You’ve made it to planting day—always an exciting milestone, especially if you’ve pre-sprouted your corms. Proper preparation and planting techniques are essential to give your ranunculus the best possible start.
Preparing the Growing Beds
Ranunculus thrive in soil rich in organic matter but are prone to powdery mildew, making proper preparation key. While we cover soil amending in detail in our transplant blog, here’s what we do:
Use quality compost and a well-balanced slow-release fertilizer for steady growth.
Ensure beds are well-draining to prevent waterlogging.
Add drip irrigation to provide consistent moisture and avoid overhead watering.
Weed cloth: This is our go-to for controlling weeds, maintaining consistent soil temperatures, and retaining moisture. Weed cloth helps us stay on top of farm tasks during the busy spring season, allowing us to focus on planting out heat-loving crops, events, and weddings without the ranunculus patch being overtaken.
Pro Tip: Use a silage tarp ahead of time to help smother weeds and prepare your beds efficiently. This can save you hours of labor and ensure your weed cloth is even more effective.
Looking for reliable tools to streamline your bed preparation? Explore weed cloth and silage tarps to control weeds, retain moisture, and ensure your growing beds are ready for success.
How to Plant Ranunculus Corms
Orientation Matters: Plant the corms with the “tentacles” pointing down, so they look like squid ready to dive into the soil.
Planting Depth: Cover the corms with about 1 inch of soil, or roughly twice the corm’s size.
Spacing: Space plants 4–9 inches apart. I plant mine at 7x7 inches for optimal airflow and reduced disease risk.
Pro Tips for Planting Success
Airflow Is Key: Proper spacing helps prevent fungal diseases like powdery mildew and botrytis, especially in humid climates.
Water Wisely: Drip irrigation keeps soil evenly moist without waterlogging.
Leverage Weed Cloth: Using weed cloth not only simplifies weed management but also creates a stable environment for healthy growth.
For detailed tips on soil preparation and transplanting, check out our transplanting guide here.
Planting ranunculus might take some extra care, but the effort is well worth it. You’re setting the stage for healthy plants that will reward you with armloads of blooms in just a few months!
A patch of Sfumato ranunculus in delicate pastel tones, showcasing their unique beauty.
Common Challenges When Growing Ranunculus
Ranunculus are undeniably stunning, but they aren’t without their challenges. While powdery mildew and weeds can be managed with good airflow and weed cloth, there are a few other hurdles to keep in mind when growing these beauties.
Fungal Diseases
Ranunculus are highly susceptible to fungal issues like botrytis, blight, and pythium, which can cause corm rot or stem collapse.
Prevention Tips:
Pre-sprouting your corms helps reduce the chances of rot before planting.
Use preventative fungicides during the soaking or pre-sprouting process.
Maintain consistent watering and avoid over-saturation.
For Powdery Mildew: Focus on maintaining good airflow and consider sulfur-based sprays if mildew becomes a problem.
Salt Build-Up in Soil
Stem collapse in ranunculus can result from several factors, including diseases, calcium deficiencies, and, in our experience, salt build-up in the soil. Salts can accumulate naturally in some soils or from repeated applications of composted manure or fertilizers. Over time, salts may concentrate in the root zone, especially with localized watering methods like drip irrigation, stressing plants and interfering with water uptake.
Solution: Flush the soil monthly with water containing a natural surfactant, such as yucca extract, to help leach salts below the root zone and restore balance.
Pro Tip: Regularly test your soil to monitor nutrient levels and salinity. If calcium deficiency is detected, consider incorporating calcium amendments, such as gypsum, to strengthen plant structure and prevent collapse.
Pests
Ranunculus are magnets for aphids and thrips, especially early in the season.
Integrated Pest Management (IPM): Early in the season, we spray with Pyganic to manage pests before beneficial insects like ladybirds arrive.
Ladybirds to the Rescue: We’ve found the best long-term control for aphids to be the presence of ladybirds, which naturally keep pest populations in check.
Other Pests: Watch for slugs or spider mites, which may require handpicking or targeted sprays.
Pro Tip: Create an environment that attracts beneficial insects by planting companion plants or leaving areas of the farm undisturbed to provide shelter.
Sudden Weather Swings
Erratic weather can stress plants and impact their productivity. Gradually acclimate pre-sprouted corms to outdoor conditions to reduce transplant shock. Having infrastructure like tunnels or shade cloth on hand ensures plants are protected from freezing temperatures and unexpected heat spikes.
A Note for Beginners: Ranunculus can be high-maintenance, but every challenge is an opportunity to learn. Over time, you’ll develop systems and strategies that work best for your farm, and the reward of vibrant, full blooms makes it all worthwhile.
Harvesting Cloni Nuance ranunculus, one stem at a time, for stunning spring arrangements.
Harvesting and Post-Harvesting Care of Ranunculus Flowers
After months of careful planning, planting, and tending, the moment has finally arrived—harvesting your first ranunculus blooms! To ensure the best vase life and quality, proper harvesting and post-harvest care are essential.
When to Harvest Ranunculus
Ranunculus are best harvested in the “marshmallow” stage—when the bloom feels squishy, like a marshmallow, and the petals are just beginning to unfurl.
For longer storage, harvest while the buds are still in the marshmallow stage.
If the blooms will be used soon, they can be harvested slightly more open.
Some growers prefer harvesting after blooms have opened and closed 2–3 times in the field, ensuring the flowers are fully mature.
Best Timing: Harvest early in the morning or late in the evening when the flowers are most hydrated, reducing stress on the plants.
How to Harvest Ranunculus
Cut stems at the base of the plant to maximize stem length.
Remove side buds, if present, to focus the plant’s energy on the main bloom and extend vase life.
Strip any leaves that may sit below the waterline in your harvesting bucket.
Pro Tip: Leaving side buds on can create a fuller look for bouquets but may slightly reduce vase life.
Post-Harvest Care
Prepare the Bucket: Fill your bucket with 2–3 inches of clean, cool water and add a floral preservative, such as Chrysal CVBN tablets, to reduce bacteria and keep stems fresh.
Storage: Ranunculus do best in a cooler set at 32–34°F for longer storage (up to 2 weeks). For shorter-term storage (a few days to a week), maintain a cooler temperature of 34–38°F.
No Moisture on Heads: Ensure the flower heads are dry before placing them in storage to prevent rot.
Dry Storage for Events: For transporting blooms to weddings or markets, storing them dry in flower boxes or sleeves inside a cooler is a great option to maintain their condition.
Transporting Ranunculus
Use floral sleeves or buckets with grid tops to secure stems during transit.
Always transport blooms in a cool environment to minimize stress and maximize vase life.
Expected Vase Life
Ranunculus have an exceptional vase life of 7–10 days when properly cared for, making them a favorite for weddings, events, and market bouquets.
A spring-inspired arrangement featuring ranunculus and other seasonal favorites, perfect for weddings and events.
Ranunculus in Design Work
Ranunculus are a dream to work with in floral design. Their delicate, multi-petaled blooms and strong stems make them versatile for a wide range of arrangements, from lush, romantic bouquets to minimal, modern compositions.
Focal Flowers or Supporting Roles
Ranunculus can shine as a focal flower in arrangements, thanks to their striking blooms, or play a supporting role by complementing other statement flowers like roses, peonies, or dahlias.
Perfect for Weddings and Events
These flowers are a favorite for weddings and events, adding elegance and romance to:
Bouquets
Centerpieces
Installations
Cake flowers
Their excellent vase life ensures they stay fresh throughout a full day of celebrations, making them a reliable choice for florists. However, their stems can be fragile for installs, this is where using water tubes come in handy!
Curious about the rewards of working in weddings? Check out our blog Why Become a Wedding Farmer-Florist? Unveiling the Rewards and Creative Joys to discover if this path aligns with your flower farm journey.
Wearables and Specialty Pieces
Ranunculus are fantastic for wearables like corsages, boutonnieres, floral crowns, or even dog collars for pet-friendly events. Their ability to hold up out of water for extended periods makes them perfect for these designs.
Pro Tip: Wire ranunculus heads for wearables to ensure they stay secure and don’t snap off during use.
Pairing Ranunculus with Other Flowers
Ranunculus pair beautifully with a wide range of blooms. For spring arrangements, try combining them with anemones, sweet peas, and dusty miller for soft, elegant looks. Their wide color range also makes them ideal for creating custom palettes to match any event theme.
Tips for Longevity and Care
Handle with Care: While ranunculus stems are strong, the blooms can be fragile. Avoid unnecessary handling to prevent bruising or damage.
Rehydrate Before Use: Always rehydrate ranunculus after transport, especially if they’ve been stored dry, to restore their freshness.
Use Flower Food: Incorporating flower food into arrangements can extend their vase life even further.
Ranunculus bring elegance, versatility, and longevity to floral designs, making them a staple for weddings, events, and everyday arrangements.
Vibrant Nuance ranunculus blooming in the growing patch, a stunning highlight of the spring field.
Knowing When Ranunculus Plants Are Done for the Season
Ranunculus plants will let you know when it’s time to say goodbye for the year. As the temperatures rise and the days lengthen, these cool-loving blooms begin to wind down.
Signs Your Ranunculus Are Finished
Fewer Blooms: Flower production slows significantly or stops altogether.
Yellowing Foliage: The leaves start to yellow and die back naturally.
Heat Stress: Temperatures consistently above 70°F can cause the plants to go dormant or decline.
At this stage, you can either clear the beds to make room for summer crops or prepare to save the corms for next season.
Can I Save My Corms for the Next Season?
The answer is both yes and no, depending on the variety you’re growing and your location.
Checking for Patents:
Many ranunculus varieties are patented, which legally prevents you from saving and reusing the corms for propagation. Before attempting to save your corms, check with your supplier to ensure it’s allowed.
If Saving Is Allowed:
For varieties that aren’t patented, saving corms is straightforward:
Let Them Die Back: Allow the plants to naturally die back in late spring or early summer. You can help this process by cutting back on water.
Dig Them Up: Once the foliage is completely yellowed, carefully dig up the corms.
Clean and Dry: Rinse off any soil, then lay the corms out to dry completely in a cool, shaded area.
Store Properly: Keep the dried corms in a cool, dark location with good airflow until it’s time to plant again.
Considerations for Saving Corms:
Saved corms often produce smaller blooms and shorter stems in subsequent years.
In harsher climates, the freeze-thaw cycle may damage stored corms.
For consistent quality, many growers choose to purchase fresh corms annually.
Pro Tip: If you want to experiment with saving corms, try it on a smaller batch while purchasing fresh ones to ensure a reliable harvest.
Bright pink Nuance ranunculus carried in a vintage sap bucket, ready for market or design work.
Wrapping Up: The Beauty and Rewards of Ranunculus
Growing ranunculus may come with its challenges, but the rewards are truly unmatched. From their delicate, multi-petaled blooms to their versatility in design work, ranunculus have a way of capturing hearts and elevating any arrangement.
With proper planning, care, and a few troubleshooting tips under your belt, you’ll be well on your way to growing these springtime treasures successfully. Whether you’re filling bouquets for market, designing for weddings, or simply adding beauty to your garden, ranunculus are worth every bit of effort they demand.
Ready to start your own ranunculus journey? Dive into our other guides, including:
Want a quick refresher on everything you need to know? Watch our Five-Minute Flower Friday video on ranunculus to get started!
We hope this guide inspires you to embrace ranunculus and their incredible potential for your farm, garden, or floral designs.
We are looking forward to sharing more blooms with you soon.
Jessica & Graham
