Ranunculus are beautiful blooms that can add a pop of color to gardens in spring and early summer. Their rose-like flowers and delicate ruffled petals make them a favorite for cut flower arrangements. But many gardeners have questions about how to grow these beauties year after year. Are ranunculus annuals that need replanting every spring? Or are they perennials that come back on their own? The answer is…it depends!
I’ve grown ranunculus in my own garden for years and done lots of research on how to keep them thriving. Here’s what I’ve learned about whether ranunculus are annuals or perennials and the best way to grow them in different climates.
The Tricky Thing About Ranunculus Plants
Ranunculus plants (Ranunculus asiaticus) are technically tender perennials. That means the foliage dies back each winter but the bulb-like corms underneath the soil survive and sprout again in spring.
However, ranunculus corms can’t tolerate freezing winter temperatures. In zones 8-11, where winters stay mild, ranunculus are hardy perennials. But in colder zones, they can’t overwinter outdoors and have to be replanted annually.
Even in warmer climates, many gardeners treat ranunculus as annuals and replant the corms every year. This avoids any risks from unusually cold snaps. It also helps control diseases and overcrowding issues that can happen when corms stay in the ground for multiple years.
So in most locations, ranunculus function more as annuals than true perennial plants But with some special care, you may be able to keep them returning year after year
Growing Ranunculus as Annual Flowers
For gardeners in zones 7 and colder, growing ranunculus as annuals is the easiest approach. Here’s how to do it:
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Buy pre-sprouted corms in late winter or early spring. Look for plump corms just starting to show green shoots.
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Plant in spring after the last frost date. Ranunculus prefer sunny spots with very well-draining soil. Space corms 4-6 inches apart and 2 inches deep.
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Enjoy the flowers throughout spring and early summer. Cut blooms for bouquets to encourage more blooming.
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When foliage dies back in summer, dig up corms and discard them or give them away. Replant fresh corms the following spring.
One downside to this annual approach is you’ll have to purchase new ranunculus corms each year. But you’ll getabundant flowers and won’t have to worry about overwintering.
Overwintering Ranunculus as Perennials
In zones 8-11, ranunculus can survive winter outdoors and regrow as perennials. But you’ll need to choose cold-hardy varieties and provide some special care. Here’s how to overwinter ranunculus:
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Plant ranunculus corms in fall, several weeks before your first frost date. Choose Italian varieties like the Elegance, Cloni, or Cloni Pon Pon series which are bred for overwintering.
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Make sure the planting spot has excellent drainage. Heavy winter rains can rot corms if drainage is poor. Amend soil with compost or sand if needed.
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Consider planting in containers for better control over winter moisture. Bring pots into an unheated garage or shed if hard freezes are expected.
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Mulch over planting areas with a thick layer of straw or leaves for insulation. Cover with hoop tunnels, cold frames, or frost cloth if temperatures drop below 30°F.
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When foliage fades in summer, dig up corms and store them in a cool, dry spot over winter. Replant in fall for seasonal color.
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Divide overflowing clumps every 2-3 years to control crowding and disease. Discard any soft or rotten corms.
Put in this extra care, and your overwintered ranunculus may thrive for years as perennial flowers.
Growing Ranunculus in Containers
Containers offer an excellent way to grow ranunculus, whether you treat them as annuals or perennials. Use pots at least 12-14 inches wide and deep with drainage holes. For potting mix, use a lightweight blend containing compost along with perlite or vermiculite to prevent soggy soil.
Make sure containers have drainage holes and use saucers to catch excess water. Move pots under shelter in winter or dig up corms for storage. Divide rootbound plants every 2-3 years.
Container growing allows you to position ranunculus in the best conditions. Move them into full sun in spring and part shade in summer when temperatures climb. In fall, containers can be buried in garden beds or moved into protected areas for winter.
Best Ranunculus Varieties for Cut Flowers
One of the joys of growing ranunculus is using the gorgeous blooms in floral arrangements. Some top cut flower varieties include:
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Tecolote: Large, ruffled, peony-like blooms in vibrant shades like pink, purple, yellow, and orange. Long-lasting in water.
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Magic Mixture: A colorful blend of solids and bicolors in both double and single flower forms.
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Fata Morgana: Unique green-tipped white blooms blushed with pink. Striking in bouquets.
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Bloomingdale: Fully double, rose-shaped flowers in an eye-catching mix of picotee patterns.
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Elegance: An Italian line bred for overwintering with large, lush blooms. Available in solids and two-tones.
For the biggest bouquets, plant early, midseason, and late blooming varieties together to extend the harvest.
Common Problems With Ranunculus
When growing ranunculus, watch out for a few potential problems:
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Rotting corms: Caused by overwatering or poorly drained soil. Allow soil to dry between waterings.
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Foliar diseases: Powdery mildew, blights, and mold can occur. Avoid wet foliage and don’t overcrowd plants.
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Failure to bloom: Usually caused by inadequate sunlight. Ranunculus need at least 6 hours of direct sun daily.
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Pest damage: Slugs, snails, nematodes or other pests can feed on plants. Remove by hand or use organic remedies if needed.
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Corm decline: Old, overcrowded corms may grow weakly. Dig and divide corms every 2-3 years to revitalize.
Catch issues early and you can still have success with ranunculus. Be prepared to pull plants if they become diseased to avoid spreading problems.
Are Ranunculus Worth the Effort?
While ranunculus do require some special care, their gorgeous blooms make it worthwhile in my book. Follow the tips above to find the best way to grow ranunculus in your climate.
Treat them as annuals or go the extra mile to overwinter them as perennials. Either way, you’ll be rewarded with delightful flowers that are perfect for bouquets. Plant ranunculus this year and enjoy these harbingers of spring!
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Where to Plant Ranunculus
Ranunculus are cool season flowers that grow best in spring-like temperatures of about 55°F. In warm climates (zones 8-10), the corms are planted in the fall so they will bloom in late winter and early spring. Plant ranunculus in beds and borders, cutting gardens and containers. They are good companions for other spring flowers such as primroses, pansies and larkspur.
In climates where ranunculus are not winter hardy (zones 4-7), the corms are usually planted in late winter or very early spring for flowers in early summer. In these areas, home gardeners often grow ranunculus in containers rather than in the garden. Containers make it easier to control light and soil moisture.
Flower farmers and other commercial growers usually grow ranunculus in a greenhouse. To ensure flawless blossoms, its important to carefully control air temperatures and well as the amount of light the plants receive. When ranunculus are grown in a greenhouse or under low tunnels, the bulbs are either planted in fall for flowers in late winter and early spring, or in late winter for flowers in spring and early summer.
To learn more, read Cut Flower Favorites: Freesia and Ranunculus.
Start with a Quality Plant
Ranunculus grow from corms that resemble little claws. Large corms contain more stored food energy than small corms, and will give you a stronger plant with more flowers. Longfield Gardens supplies 6/7 cm ranunculus corms so you can enjoy the biggest, brightest blooms.
How I Grow Ranunculus (+ Schedule of Planting Dates)! // Garden Answer
FAQ
Do ranunculus come back every year?
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Perennial in Warm Climates:In zones 8-10, ranunculus are considered perennials, meaning they can survive the winter and bloom again the following year if the corms (underground stems) are left in the ground.
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Annual in Colder Climates:In colder regions (zones 4-7), ranunculus are typically treated as annuals, meaning they are planted each spring and the corms are not likely to survive the winter.
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Corm Storage:If you live in a colder climate and want to try to overwinter ranunculus, you can dig up the corms in the fall, store them in a cool, dry place, and replant them in the spring.
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Planting Time:In warmer zones, ranunculus can be planted in the fall for spring blooms, while in colder zones, they are typically planted in late winter or early spring.
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Growing Conditions:Ranunculus prefer cool, moist conditions and well-drained soil. They also need full sun to partial shade.
Do ranunculus bulbs multiply?
Yes, ranunculus plants multiply through their underground structures called corms, which are swollen underground stems that store nutrients and energy for the plant. As the ranunculus plant grows, it produces new corms, often referred to as daughter corms, around the original corm.
Can you leave ranunculus in the ground over winter?
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Hardiness:Ranunculus are hardy in USDA zones 8 to 10, meaning they can tolerate mild winters.
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Perennials:In these zones, ranunculus can be grown as perennials, meaning they will return the following year from the same corms.
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Overwintering:You can leave the corms in the ground after the growing season and they will re-sprout in the spring.
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Protection:While they are hardy, it’s a good idea to protect them from extreme cold or wet conditions, especially if you live in a zone on the cooler end of the range (e.g., zone 8).
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Mulch:Apply a layer of mulch, such as straw or shredded leaves, around the base of the plants to help insulate the soil and protect the corms from freezing temperatures.
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Frost Cloth:In case of extreme cold, you can cover the area with a layer of burlap or a frost blanket for added protection.
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Timing:Plant ranunculus in the early fall when soil and air temperatures are still warm enough for root development.
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Digging and Storing (for colder climates):If you live in a colder climate (e.g., zone 6b or below), you may need to dig up the corms and store them indoors during the winter, as they are not as hardy in colder conditions.
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Corm Care:Once the foliage turns brown, you can dig up the corms, brush off the soil, and store them in a cool, dry place until the following spring.
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Pest Control:Be aware that voles and moles may be attracted to ranunculus corms, so it’s a good idea to take steps to protect them from these pests, especially if you choose to leave them in the ground.
Do ranunculus like full sun or shade?
- Sunlight Requirements: Ranunculus are cool-season plants that need plenty of bright light to thrive.
- Full Sun vs. Partial Shade: While they prefer full sun, they can tolerate partial shade, particularly in areas with very hot summers.
- Hot Climates: In hot climates, providing some afternoon shade can help protect ranunculus from excessive heat and extend their flowering period.
- Soil and Water: Ranunculus need moist, well-draining soil and regular watering, especially when they are actively growing.
- Planting: Plant the corms 2″ deep and about 9″ apart.
- Dormancy: Once the weather warms up, ranunculus will go dormant, which is normal.
- Hardiness: Ranunculus are hardy in zones 8-10 and suitable for zones 4-7.
Are Ranunculus cut flowers?
Today, ranunculus are grown as cut flowers mostly, though there are some shorter bedding varieties that are sold at plant nurseries in the Spring. Ranunculus reproduce by tubers and seeds. Ranunculus is a tender perennial flower that grows from fleshy, underground structures called tubers.
Is Ranunculus a perennial?
Today, ranunculus are grown as cut flowers mostly, though there are some shorter bedding varieties that are sold at plant nurseries in the Spring. Ranunculus reproduce by tubers and seeds. Ranunculus is a tender perennial flower that grows from fleshy, underground structures called tubers. Are Ranunculus perennials?
Are Ranunculus flowers good?
Ranunculus flowers are true showstoppers and are perfect flowers to grow in the garden in beds, borders and containers. Be sure not to forget to make the most of these fabulous blooms as fresh cut flowers for summer bouquet arrangements. When it comes to growing these excellent flowers, here is everything you need to know! What are Ranunculus?
What color are Ranunculus flowers?
Ranunculus flowers are beloved by florists and gardeners for bouquets and cut flower arrangements. These long-blooming perennials come in colors like yellow, pink, orange, red, purple, and white. Symbolizing charm, attraction, and the early stages of romance, ranunculus are known for their multilayered petals that appear similar to roses.
When do Ranunculus flowers bloom?
Ranunculus flowers tend to bloom from March through May, but bloom time may vary by species and location. Once bloomed, ranunculus flowers produce many layers of petals in an almost rose-like structure. These flowers are available in many colors and offer a light, sweet fragrance.
Are Ranunculus fussy?
Ranunculus aren’t fussy, but they do need the right conditions and care to produce plenty of their sought-after flowers. Hardy perennial ranunculus should be planted in full sun or partial shade. If they are planted in full shade, they will not flower.