How To Grow And Care For Ranunculus

Ranunculus is a favorite amongst flower lovers for good reason. With its defined round shape and whisper-thin petals, ranunculus inspires comparisons to roses or peonies. The blooms are available in just about every color you could want and last a long time as a cut flower, making them a great choice for romantic arrangements or bouquets.

Ranunculus thrive in full sun and in organically enriched, well-drained soil. If your soil is too wet, consider building some raised beds so you can control the environment for your ranunculus. Set roots with prongs down, 1-2 inches deep and 6–8 inches apart. Water thoroughly, then withhold water until leaves emerge. Birds are fond of ranunculus shoots, so protect sprouting plants with netting or wire. Or start plants in pots or flats, then set them in the garden when they're 4-6 inches tall (a size that will be less appealing to pesky birds.). You can also start with nursery-grown seedlings. Remove faded flowers to encourage more bloom.

When flowering tapers off and leaves start to yellow, stop watering the plants and allow the foliage to die back. Where tuberous roots are hardy in the ground, they can be left undisturbed as long as soil can be kept dry during summer. Some gardeners dig plants when foliage turns yellow; cut off the tops; let roots dry for a week or two; and store them in a cool, dry place until planting time. But because roots don't store that well, most people find it simpler to discard the plants and set out new roots when the time comes.

According to the ASPCA, ranunculus is toxic to pets.

Plant Attributes

Common Name	Ranunculus, Persian buttercup
Botanical Name	Ranunculus asiaticus
Family	Ranunculaceae
Plant Type	Perennial, Bulb
Mature Size	1-2 feet tall, 1-2 feet wide
Sun Exposure	Sunny, but can vary by species
Soil Type	Loamy, Sandy, Well-drained
Soil pH	Acidic
Bloom Time	Spring, Summer
Flower Color	White, pink, yellow, purple, red, orange
Hardiness Zones	Varies by species
Native Area	Mediterranean, Asia
Toxicity	Toxic to plants

Ranunculus Care

The care of ranunculus can differ depending on your USDA hardiness zone. If you plant them in Zone 8 or above, they will grow as perennials. The care is simple. Once established, water as needed and consider adding water-soluable fertilizer to boost blooms. At the end of the season, let the plant die back. The bulbs in the ground prefer dry soil when dormant, so if you can’t provide that, it’s best to treat them as an annual.

In those garden Zones below Zone 8—LS, CS, and TS—plant ranunculus after the last frost, setting the roots facing down and cover them with soil. Give ranunculus a good watering to start and wait until you see the leaves begin to emerge before watering more. Add a water-soluble fertilizer, following package directions.

Regardless of where you live, the one thing you’ll want to monitor is the moisture level of the soil. If the ground is too wet, there’s a high chance that the plant will rot.

Light

Ranunculus prefer full sun to grow and bloom best, but light needs vary. 

Soil

Plant ranunculus in loamy or sandy soil that is slightly acidic and with good drainage.  You can lighten heavy soil by amending with peat moss. If the ground conditions seem unfavorable, you can always plant ranunculus in raised beds for a more controlled environment. 

Water

You can plant ranunculus bulbs dry, but you can also soak them in water for up to four hours before planting. This will stimulate growth. After you plant ranunculus in your garden, water the garden bed well and be patient. After you start to see the new plants sprouting up, you can begin a regular water routine. Ranunculus prefer somewhat moist soil, so don’t overdo it.  It’s always good to wait until the soil is a little dry before watering.

Temperature and Humidity

Ranunculus likes cool spring weather, so add mulch around the base of the plant to protect it from the summer heat. If you don’t, expect ranunculus to go dormant once the temperatures exceed 90 degrees. This plant likes the humidity in our Southern climate and should grow well under normal conditions. If things are unusually humid, and the plant is too wet, the bulb will rot and the plant will die.

Fertilizer

After the leaves of ranunculus begin to appear, you can begin a fertilizing routine. Deliver a water-soluble fertilizer on a biweekly schedule, following the product label instructions for best results, says Dr. Gary Bachman, extension specialist at Mississippi State University.

Types of Ranunculus

This very large genus comprises about 250 species of widely differing habit and appearance, but the three listed here are the most common types of ranunculus. None are bothered by deer.

Persian Buttercup (r. asiaticus)

Ranunculus Asiaticus ‘Persian Buttercup’ is native to Asia Minor and grows well in Zones 8–11. This tuberous-rooted plant can grow to up to 2 feet tall and wide with fresh green, almost fern like leaves. This ranunculus blooms profusely in spring when each flowering stalk bears one to four 3- to 5-inch wide, semi-double to double blooms that resemble a small peony bloom. The flowers grow in white, cream, and many shades of yellow, orange, red, and pink. The popular Tecolote Giant is available in single colors, mixed colors, and picotees, which are a solid color edged with a secondary color. The Bloomingdale variety offers the same range of colors on dwarf plants that grow 8 to 10 inches and grow well in the ground or in pots.

Lesser Celandine (r. ficaria)

Ranunculus Ficaria, called ‘Lesser Celandine,’ originates in Europe and Eastern Asia, so it grows well in all parts of the South, Zones 6–9. This perennial ranunculus can be aggressive, spreading by sending bulblets on stems and with underground tubers. The plant forms a dense mat of heart-shaped, 1- to 2 inches-wide, shiny, dark green leaves that mound to about 3 feet tall. The bright yellow, buttercup-like flowers rise above the foliage in spring and die back in late summer. This variety grows well in full sun or part shade.  It is such an easy grower, in fact, that it has become an invasive weed in some areas. Less aggressive selections include 'Brazen Hussy,' with purple-black leaves; ‘Collarette,’ with heart-shaped leaves marked with silver, and ‘Randall’s White’ with cream-yellow flowers and leaves marked with silver.

Creeping Buttercup (r. Repens pleniflorus)

Ranunculus Repens Pleniflorus, also known as ‘Creeping Buttercup,’ is from Eurasia and naturalized in North America. This vigorous plant has thick, fibrous roots and runners that root at the joints. The plant grows well in Zones 6–9 and forms a lush, glossy, green mat about a foot tall and 6 feet wide. The leaves are roundish and have three tooth-edged, 2 inch-long leaflets. In spring, this variety of ranunculus blooms with small, bright yellow flowers on long stems. This deciduous ground cover grows in full sun to deep shade and can be invasive when planted in constantly moist soil.

Pruning Ranunculus

There’s no need to prune ranunculus, but deadheading the spent blooms as they fade will redirect the plant’s energy to produce more blooms.

Propagating Ranunculus

If you plant ranunculus as a ground cover, you can propagate the plant to help it spread. In other varieties, dividing the ranunculus bulb can help you control the size of the plants and the tidy look of your garden bed. If you live in Zone 8 or above, dig up bulbs with a shovel and divide the bulbs with a sharp knife. Plant the new divisions with roots facing down. Below Zone 8, ranunculus is considered an annual.

How to Grow Ranunculus by Seed

As your ranunculus flowers begin to fade, pinch off the flower and put them in a brown paper bag to dry. In a week or two, you can give the bag a good shake to harvest the tiny seeds. Start them inside under grow lights. Germination takes about two weeks. After the plant has a few leaves, you can move them to outdoor containers after any possibility of a spring frost is behind you.

Potting and Repotting Ranunculus

If you’re growing ranunculus as an annual, potting them in a container is a good way to enjoy this pretty flower. Fill your pot with all-purpose potting mix and space them a few inches apart. Water and place the pot in full sun.