Are ranunculus annual or perennial? It depends …

Sometimes called ‘the rose of spring’ or ‘Persian buttercup,’ ranunculus come in singles or doubles, smooth-edged or ruffled, in solids and picotees.

Sometimes called ‘the rose of spring’ or ‘Persian buttercup,’ ranunculus come in singles or doubles, smooth-edged or ruffled, in solids and picotees.
Erica Browne Grivas

The tight globes of layered ranunculus blooms are almost too perfect to be believed. You might think they are crepe paper concoctions, but they are very real. Growing from corms resembling tiny brown octopi or claws about the size of a quarter, greenhouse-grown plants arrive like magic at nurseries in March and April, when gardeners are at their most flower-deprived and color-hungry, alongside primroses and pansies.

The ranunculus family includes the dreaded creeping buttercup, the fleeting spring anemones and these lovelies. Sometimes called “the rose of spring” or “Persian buttercup,” ranunculus come in singles or doubles, smooth-edged or ruffled, in solids and picotees. They are robust cut flowers lasting up to 10 days in a vase.

It was love at first sight for me. Years ago, my then-boyfriend lived in an apartment facing a paved courtyard in the West Village of New York City. He didn’t have access to the garden, but the woman who did, called Sara, was an experimental container gardener with a trained eye for plants. I think she had a larch, but in spring she had these elegant lollipops on stems, and the first chance I got I hollered across the courtyard to ask her what those crazily beautiful things were. (New Yorkers aren’t shy about that.)

Fast-forward to gardening now in Seattle, where the question has nagged at me over many springs — can we, or I — get ranunculus to stick around year after year in the garden?

In the fall, I made the leap and purchased some salmon-toned Elegance ranunculus from Easy to Grow Bulbs, easytogrowbulbs.com. When they arrived in mid-November, I wasn’t sure whether to store or pot them up, so I reached out to customer service — and that’s when the confusion deepened.

The Easy to Grow Bulbs site says in zones 8 and warmer, plant in the fall; in cooler places, store and plant in spring. But we couldn’t agree on my zone. Although the USDA map shown on the site lists Seattle as 8b, EGB’s online zipcode calculator puts us as 7B, which the customer service representative reiterated. The USDA’s own calculator, planthardiness.ars.usda.gov, has us at 8B, though we used to be 8 until 2012.

So, adamantly sticking with zone 8, my option was to store in a cool, dark place like a pantry shelf in a mesh or paper bag, or plant. I planted in a container the first week of December to help boost drainage. (This was based on my success of one single “Tecolote” making it through to a second year — barely and briefly — in a window box.) Here’s hoping!

This year, I gained some local knowledge. At the Northwest Flower and Garden Festival, I saw a new booth called The Dahlia House, selling ranunculus corms. Anne Long runs Dahlia House, thedahliahouse.com, from the Skagit Valley, growing and arranging ranunculus, their cousins the tuberous anemones and dahlias, and she’s taught at Floret Farms, Christianson’s Nursery and at the flower festival. 

Long was selling corms on her website in mid-late March, but if you haven’t ordered corms yet, you can buy growing plants.

By happy accident, I met Emily Mitchell, @lollibirdgardensrc, at the booth. She grows Anne’s varieties, along with other easy-to-grow cut flowers, from her Magnolia greenhouse and sells them from her sidewalk from 10 a.m. to 1 p.m. on Saturdays at 3220 Magnolia Blvd West. This year, the season runs from March 18-May 20.

I learned from Long’s free online webinar that the most resilient varieties of ranunculus for our area are the Italian lines, with names like Sfumato, Giallo and Cloni Nere. Italian ranunculus bulbs offer sturdier stems, a higher petal count and, most importantly, adapt to a wider range of climates, potentially including our well-watered one. They are harder to find, but worth seeking out. Series to look for are Cloni, Cloni Pon-Pon and Elegance.

By the way, many of the varieties you’ll see at nurseries are not the Italian types. In zones 7 and warmer, planting in fall, in a sunny spot with excellent drainage is your best bet, with greenhouse or protected spring growing a close second. Long digs hers in fall, as many dig their dahlias, but they can overwinter here. This is where the “it depends” comes in.

Ranunculus are hardy to about 30 degrees and need protection with row cover fabric below that.

More tips from Long:

Soaking corms in water for four hours or so helps sprout them. Then plant 2 inches deep, claws down. You should see blooms in three or four months. The more you cut, the more blooms will come. Cut the stalk all the way to the base. Fertilizing during and after blooming will keep the plants strong.

They will bloom until temperatures reach 80 degrees or so, and then they’ll slip into dormancy. If digging, Long says wait until the foliage has yellowed.

Floretflowers.com says they can overwinter in zones 7 and warmer depending on how cold the winter is, how well-drained the soil and which critters might nosh on your bulbs. Bottom line? Long digs hers in fall and Floret Farms replants extra every year to never be without ranunculus. It sounds like experimentation is necessary to find the perfect microclimate to grow these beauties — or just dig them and save for next year’s bouquets.