Ranunculus: How To Plant, Care and Grow Terrific Flowers

When to plant Ranunculus Flowers?

• In hardiness zones 8-11, where temperatures do not drop below 10°F (-12 C), the best time to plant Ranunculus corms outdoors is in the fall.
• Not sure about your growing zone? Check here.
• In colder areas (zone 7 and below), the best time to plant Ranunculus corms outdoors is in late winter, or early spring after the danger of frost has passed.
• Ranunculus may be started indoors as early as 12 weeks before the average last frost date (for earlier blooms).
• It typically takes about 90 days from planting to flowering, depending on weather conditions and variety.

Where to plant Ranunculus Flowers?

• Best flowering occurs in full sun. Provide some afternoon shade in hot climates.
• Ranunculus thrive in moderately moist, sandy, or loamy, well-drained soils. Good drainage is absolutely essential for success. They do not tolerate wet or soggy soil, which can lead to rotting.
• Ranunculus look wonderful in beds and borders, cutting gardens, Mediterranean gardens, or containers.
• In addition to their garden uses, Ranunculus are also very important as cut flowers.

Choose The Right Ranunculus Bulbs (Corms)

• Choose corms that are large, firm, and plump.
• The size of the corms is highly correlated to the number of flowers per plant. The larger the corm, the bigger the plant and the more spectacular the flowers.
• A jumbo corm will produce up to 35 flowers, while a number 1 corm will produce up to 20 flowers, a number 2 corm will produce up to 12 flowers, and a number 3 corm will produce up to 7 flowers.

How to plant Ranunculus from corms?

• It is advisable to soak the corms for 1-4 hours before you plant them or water them well when planting.
• In garden beds, plant the corms 2 in. deep (5 cm) and 4-6 in. apart (10-15 cm) with the claw side down. Space jumbos 8-12 in. apart (20-30 cm).
• Ranunculus adapt easily to container life: you may plant the corms about 6 in. apart (16 cm).
• Avoid overcrowding the plants, and always make sure you provide good air circulation in and around the plants.
• Cover the corms with soil and water as needed.
• As long as the soil retains some moisture, do not water them again until new growth appears, usually within 15 to 20 days, to avoid rot.

How to plant Ranunculus from seeds?

• Sow Ranunculus seeds in a lightweight, peat-based seed-starting mix in late winter.
• Maintain soil temperature at 50°F (10°C). It will take 20 to 30 days for germination to occur.
• After germination, maintain seedlings indoors at about 55°F (13°C). Keep them moist and out of direct sunlight. Once seedlings have four sets of true leaves, they are ready to be moved outside as long as all danger of frost has passed.
• Plants will typically bloom 3 to 4 months after planting

Companion Plants

Plant Ranunculus with other cool-season flowers such as snapdragon (Antirrhinum), calendula, Chinese forget-me-not (Cynoglossum amabile), African daisy (Arctotis), candytuft (Iberis), Oriental poppy (Papaver orientale), sweet pea (Lathyrus odoratus), toadflax (Linaria), primrose (Primula), and pansy (Viola).

Ranunculus Care

• Once the plants are established, they prefer moderately moist soil, so water only when the soil begins to dry out.
• Ranunculus flowers benefit from regular watering and bi-weekly applications of a water-soluble fertilizer after the leaves emerge.
• Mulch around the plants to help keep the soil cool and moist at the root level.
• Deadhead spent flowers to promote new blooms.
• If you wish to use the blooms for cut flowers, you should cut the flower stems at a slant when the blooms are in the bud stage for best results. Cut in the early morning after they have had the night to recharge themselves with moisture.
• Like other spring-blooming flowers, Ranunculus flowers prefer cool spring weather and will begin to wither when the heat of summer arrives, and the soil warms up. Most gardeners treat ranunculus as annuals, disposing of them after bloom or leaving them in place to fade away.
• If you want to save your corms for next spring, dig them up before the first frost, cut off the dead foliage, and store them over winter in a dry, cool place.

How to Propagate

Ranunculus can be propagated through seeds or corms. Here are the steps to propagate ranunculus through corms:

• Wait until the flowers have faded and the foliage has died back. This is usually in late spring or early summer.
• Carefully dig up the tubers with a garden fork, being careful not to damage them.
• Separate the smaller tubers from the larger ones. The smaller tubers may not flower in the first year but will grow and produce flowers in subsequent years.
• Allow the tubers to dry in a cool, dry, and shaded area for a few days.
• Fill a container with well-draining soil or potting mix.
• Plant the tubers about 2-3 inches deep with the pointed end facing up.
• Water the soil well.
• Keep the soil consistently moist but not waterlogged.
• Place the container in a bright, sunny area.
• Once the plants have emerged and are actively growing, feed them with a balanced fertilizer every two weeks.
• In colder climates, dig up the tubers before the first frost and store them in a cool, dry, and dark place over the winter. Replant them in the spring after the last frost.

Pests and Diseases

Ranunculus plants can be susceptible to several pests and diseases, which can affect their growth and flowering. Here are some common pests and diseases that can affect ranunculus plants:

Aphids: These small insects can suck the sap from the leaves and stems of ranunculus plants, causing them to wilt and deform. They can also transmit plant viruses.

Slugs and snails: These pests can eat holes in the leaves of ranunculus plants, causing them to yellow and die. They are especially problematic in damp and humid conditions.

Botrytis blight: This fungal disease can cause the flowers and leaves of ranunculus plants to rot and turn brown. It is often caused by wet conditions and poor air circulation.

Fusarium wilt: This fungal disease can cause the leaves of ranunculus plants to turn yellow and wilt and can eventually kill the plant. It is often caused by poor soil drainage and overwatering.

Root rot: This disease can cause the roots of ranunculus plants to rot and the plant to wilt and die. It is often caused by overwatering and poor soil drainage.

To prevent these pests and diseases, it is important to plant ranunculus bulbs in well-draining soil and to water them carefully, avoiding overwatering. Proper air circulation and good garden hygiene can also help prevent fungal diseases. If pests or diseases do occur, they can often be treated with insecticidal soap or fungicides.

Frequently Asked Questions

Do ranunculus grow back every year?

Ranunculus is commonly grown as an annual in most areas. In areas with mild winters and well-draining soil, the plants may survive and grow back the following year. However, in colder climates, the corms are unlikely to survive the winter and will need to be replanted in the spring if desired.

Is ranunculus a sun or shade?

Ranunculus prefers full sun to partial shade, with at least 6 hours of direct sunlight per day.

How poisonous is ranunculus?

Ranunculus is considered toxic and can cause irritation and dermatitis when the sap comes into contact with the skin. Ingesting large amounts of the plant can also cause gastrointestinal distress. It is important to handle ranunculus with care and keep it out of reach of children and pets.