How to Grow Ranunculus: Planting Tubers, Timing and Care

Plant ranunculus tubers 2 inches deep with the root claws pointing down, in full sun and soil with excellent drainage, in fall where winters are mild or in late winter to early spring where they are cold. NC State calls ranunculus a tuberous-rooted herbaceous perennial in the buttercup family, sometimes grown as an annual. It is semi-hardy, with injury below 28°F (NC State), and Clemson says gardeners in colder climates (zones 3 to 7) treat it like an annual. It flowers about 90 days after planting (Clemson).

Sun: Full sun
Water: Moderate
Origin: Middle East
Container friendly: Yes
Soil: Excellent drainage; no heavy clay (NC State)
Planting depth: 2 in, root claws down
Spacing: 6–8 in apart
Cold limit: Injured below 28°F (-2°C)
Bloom: About 90 days after planting; up to 6–7 weeks

What ranunculus are

NC State describes ranunculus as a tuberous-rooted herbaceous perennial in the buttercup family (Ranunculaceae), sometimes grown as an annual. Clemson calls what you plant “corms” and NC State calls them “tubers”; both mean the dry, clawed storage roots sold for planting. The photo at the top of this page shows the layered, ruffled blooms.

Sun, soil and water

NC State says ranunculus do best in medium moisture, in full sun, with excellent drainage. They do not tolerate heavy clay soils (NC State). Before planting, Clemson says to pre-soak the corms in room temperature water for several hours.

When to plant ranunculus

The timing depends on how cold the winter is, and the sources give three answers.

Clemson, mild winters

Plant in fall. Corms overwinter in the ground in most of South Carolina.

Clemson, colder winters

Plant in late winter or early spring, once extreme hard frost dates have passed.

NC State

Several weeks before the last frost date.

Iowa State, indoor start

Gardeners and greenhouse growers start from dry, almost woody tuberous roots about 12 weeks before the average last frost date.

The first three give an outdoor window that moves with the climate. Iowa State’s 12 weeks is a different method: starting the roots ahead of the last frost date.

Ranunculus planting months from our sources
Zones	January	February	March	April	May	June	July	August	September	October	November	December
Zone Mild winters: plant tubers Oct–Nov										October: plant tubers	November: plant tubers
Zone Colder winters: plant tubers Feb–Mar		February: plant tubers	March: plant tubers

Plant tubers

Clemson says fall for mild winters and late winter to early spring once hard frost has passed for colder winters. The months shown are our reading of those phrases, not figures from the source. Iowa State's indoor start, about 12 weeks before the last frost date, moves with your own frost date, so it is not plotted.

Planting steps

Soak the tubers. Pre-soak in room temperature water for several hours (Clemson).
Choose a sunny, well-drained spot. Full sun, excellent drainage, no heavy clay (NC State).
Plant 2 inches deep, claws down. 6 to 8 inches apart (NC State).
Deadhead. NC State says deadheading spent flowers encourages additional blooms.

Hardiness and winter

NC State says ranunculus are semi-hardy and are injured at temperatures below 28°F in North Carolina. Clemson says that in colder climates (zones 3 to 7) they are treated like an annual, while the corms overwinter in the ground in most of South Carolina. To save the plant for next season, NC State says to dig up the tubers, cut off the tops, and store them in a dry, cool location.

Ranunculus in pots

Clemson says ranunculus perform and look great in containers.

Common ranunculus problems

SoilHeavy clayNC State says ranunculus do not tolerate heavy clay soils and want excellent drainage.ColdFrost injuryInjury occurs below 28°F (NC State). In colder climates they are treated like an annual (Clemson).TimingPlanted too early or latePlant after extreme hard frost in cold-winter areas (Clemson), or start indoors about 12 weeks before the last frost (Iowa State).

Varieties named in our sources

Variety	Best for	Type	Flower	Notes
'Venere'	Cut flowers	Cloni Success series	Huge, ruffled blooms	Named by Clemson
'Elegance Giallo'	Cut flowers	—	Yellow	Named by Clemson

Grow these next

Ranunculus is a spring flower from a dry storage root, like the tulip from a bulb and freesia from a corm. For another flower that is planted from a corm and blooms in autumn, see saffron crocus.

Frequently asked questions

When do you plant ranunculus?

Clemson says to plant in fall in areas with mild winters, and in late winter or early spring in areas with colder winters, once extreme hard frost dates have passed. NC State says several weeks before the last frost date.

How deep do you plant ranunculus tubers?

NC State says 2 inches deep and 6 to 8 inches apart, with the root claws pointing down.

Are ranunculus hardy?

NC State calls Asiatic ranunculus semi-hardy, with injury below 28°F (-2°C) in North Carolina. Clemson says in colder climates (zones 3 to 7) it is treated like an annual.

How long does ranunculus bloom?

Clemson says plants typically flower about 90 days after planting, with the flowering period lasting up to 6 to 7 weeks. NC State says to deadhead spent flowers to encourage more blooms.

Can you grow ranunculus in pots?

Yes. Clemson says it performs and looks great in containers.

Sources

Add Ranunculus to Your Fall Planting To-Do List, Clemson Cooperative Extension, Home and Garden Information Center
Ranunculus asiaticus, NC State Extension Plant Toolbox
Ranunculus, Iowa State University Extension

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