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How to Grow Ranunculus

By: Sherri Ribbey
Learn how to grow colorful ranunculus for early spring gardens and planted containers.

Close-up of ranunculus flowers: Ranunculus, or Persian buttercups, come in bright colors, perfect to usher in spring.

Ranunculus are cool-weather beauties

I’ve always admired ranunculus (also called Persian buttercup) — those beautiful flowers are real attention-getters in photos and florist’s bouquets. One spring I bought a bag of ranunculus tubers on sale at a big box store in late spring. Unfortunately, when I tried to grow them, the results weren’t great — spindly foliage and no blooms. I just chalked it up to them being difficult to grow. Then I learned they’re really cool-season flowers and thrive in the same conditions as pansies (Viola spp. & hybrids), snapdragons (Antirrhinum majus) and other spring favorites. Let me introduce you ranunculus and some of the things I’ve learned since my first disappointing effort.

Spring garden bed with Ranunculus: Frilly foliage adds a ruffled texture between the white snapdragons and yellow primrose.

How to use ranunculus in the garden

It’s easy to work in ranunculus near the front of a border. See how 12- to 16-inch-tall Bloomingdale II Orange in the photo above fills the gap between lower-growing primrose (Primula hybrids) and spiky snapdragons behind? While ranunculus look great planted in mass like this, you don’t have to buy buckets full of tubers to enjoy these pretty plants. Because each ranunculus can have several 2- to 5-inch flowers open at one time, smaller-scale plantings are just as pleasing. In areas where they’re cold-hardy, position ranunculus near perennials or shrubs to hide the foliage as it fades and the bare spot dormant plants leave behind.

Spring garden planter with Ranunculus flowers: Ranunculus is beautiful in spring containers, here with primula and creeping Jenny.

Use ranunculus in early spring planters

Ranunculus puts on quite a show — perfect for early spring containers like the one above. Flowering can continue up to five weeks, with individual blooms lingering for three to seven days in cool weather. If your soil is poorly drained, a container like this one gives the tubers just what they need to grow beautiful plants.

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How to buy ranunculus tubers

You’ll find the best selection of tubers in late fall, though there are usually some available in early spring, too. When you buy them early, store the bag in a cool, dry place that stays 50 to 55 degrees F until it’s planting time.

Where to buy ranunculus tubers

How to grow ranunculus

Grow ranunculus in full sun to part shade in moist, well-drained soil. Ranunculus are cold-hardy in USDA zones 8 to 11, grow them as annuals in colder zones.

Lots of light

With full sun, lots of organic matter and well-drained soil, ranunculus will look great and produce plenty of flowers.

Watch the water

Poor drainage causes plants to rot. Keep them moist, but not wet, while the foliage is green and flowers are blooming. But they’re more likely to keep coming back if you let them dry out as they go dormant. A bimonthly application of a liquid plant food, such as 12-4-8, will produce more flowers.

Trim to keep tidy

Deadheading helps to keep ranunculus blooming. Cut the stems back below the foliage to tidy plants.

As temperatures regularly get above 70 degrees F during the day, ranunculus slows its flowering and gets leggy. If you’re growing it as an annual, that’s a good time to pull plants out. Otherwise leave the foliage in place so the tubers can store energy for the following year. The leaves will eventually yellow; then it’s OK to cut them off at soil level.

Ranunculus tubers soaking in water: Soaking ranunculus tubers in water for at least an hour makes them less brittle so you won't break them as you plant.

How to start ranunculus tubers

In USDA zones 8 to 11 you can plant ranunculus tubers in the ground in fall — the foliage often sprouts and stays evergreen until plants bloom in late winter. In colder zones you will want to start the tubers inside.

Planting ranunculus tubers inside

Where ranunculus isn’t cold-hardy (zone 7 and colder), start it indoors. Plants grow best when daytime temperatures are in the mid- to high 50-degree F range and take 12 to 16 weeks from planting to bloom. So check your records or check online to see when these temperatures usually occur for your area and count back from there to start ranunculus tubers. This means you may need to plant them inside as early as January.


Soaked vs. unsoaked ranunculus tubers: Just an hour in a bowl of tap water above and you can see how plump the tuber at right is. The soaked ones tend to sprout first but the unsoaked ones eventually catch up

Soak ranunculus tubers before planting

I’d read about starting ranunculus tubers and saw lots of debate about whether to soak them first or not. So I talked with Ken Harr, product technical manager with Sakata® Seed, who grows lots of Persian buttercups. He said that both approaches work but the important thing about soaking is to not forget them. You can leave them in water for as little as an hour or as long as overnight, but no longer. Otherwise they get water-logged and may rot. The key with unsoaked tubers is keeping the potting mix moist but not soggy until you see growth. After that you can allow the mix to dry out between drinks.

how-to-grow-ranunculus-planting: Plant ranunculus tubers so the stem piece faces up, and the tubers curl down. Soaked tubers tend to sprout faster — in just a week or two.

Planting ranunculus tubers

  • To plant ranunculus tubers in pots inside — use at least 3-in. pots per tuber, or set several tubers in a larger pot.
  • Place potting mix in the bottom, then the tuber with the roots curling downward.
  • Top off your ranunculus tuber with 2 in. of potting mix, water and set containers where it stays 58 to 62 degrees F. There’s no need for lights until they sprout.
  • In a couple of weeks you should see new ranunculus leaves taking off. Once temperatures are 50 to 60 degrees F during the day, they can be hardened off outside, then planted in the ground.

How to store ranunculus tubers

Where ranunculus isn’t hardy, most gardeners grow them as annuals. But you can keep your favorites to grow again by digging tubers after most of the foliage has died back in early summer.

  • Brush off as much potting mix or soil as possible and remove remaining stems and leaves.
  • Then let them dry for a week to 10 days in a cool, well-ventilated spot out of direct sunlight.
  • Ranunculus tubers can go in a box of slightly moistened peat moss or vermiculite.
  • Store in a cool (around 50 degrees F), dry place until it’s time to start growing these beautiful flowers again the next growing season.

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Ranunculus varieties to try

There’s not a big size range among ranunculus; they'll grow 8 to 18 in. tall and 6 to 12 in. wide. The ranunculus you find at your local garden center are often sold as a mix, but you can get them in red, pink, orange, yellow, purple, white and bicolors. If you want a single color, your best bet is a mail-order nursery.

In addition to the varieties you will see below, you’ll also find the petite Magic™ series. It grows 8 to 10 inches tall and wide and makes a colorful edging for a path or patio. Tecolote® is one of the tallest, at 12 to 18 inches tall and 8 to 10 inches wide. Its long stems make it great for bouquets.

Mache Red ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Rich red blooms that make excellent cut flowers in early spring to early summer Light Full sun to part shade Size 12 to 16 in. tall and 10 to 12 in. wide Hardiness Cold hardy in USDA zones 8 to 11

Bloomingdale II ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Shades of white, orange, red, pink, rose and yellow in late winter to early summer Light Full sun to part shade Size 8 to 10 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Tomar Picotee ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms White petals edged in grape purple on roselike blossoms in late winter to early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Pink Shades ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Pink ruffled petals with darker centers in late winter early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Tomar Purple ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Velvety grape purple roselike blooms in late winter to early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Mache Red ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Rich red blooms that make excellent cut flowers in early spring to early summer Light Full sun to part shade Size 12 to 16 in. tall and 10 to 12 in. wide Hardiness Cold hardy in USDA zones 8 to 11

Pink Shades ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Pink ruffled petals with darker centers in late winter early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Bloomingdale II ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Shades of white, orange, red, pink, rose and yellow in late winter to early summer Light Full sun to part shade Size 8 to 10 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Tomar Purple ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms Velvety grape purple roselike blooms in late winter to early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Tomar Picotee ranunculus (Ranunculus hybrid)

Type Tuberous root Blooms White petals edged in grape purple on roselike blossoms in late winter to early summer Light Full sun to part shade Size 10 to 12 in. tall and wide Hardiness Cold hardy in USDA zones 8 to 11

Published: March 12, 2020
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