When I first saw the gorgeous blooms on ranunculus flowers, I didn’t think growing them here in the low desert of Arizona was possible. I’m glad I was wrong. Learning how to grow ranunculus is easier than you think.
The stunning rose-like blooms with tissue-thin petals almost don’t look real. Ranunculus blooms come in nearly every color on tall stems. With these five tips, learn how to grow ranunculus (even if you live in a hot summer climate like the low desert of Arizona).
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5 Tips for How to Grow Ranunculus
1. Plant ranunculus at the right time
Ranunculus grows best in spring-like temperatures of about 55°F with plenty of sunlight.
In zones seven and warmer, there are two planting windows — late fall and again in late winter or early spring. For zones cooler than zone 7, plant in the spring after the danger of frost is passed.
Floret’s top choices for ranunculus varieties are the La Belle Series which includes Salmon, Champagne, Orange, Pink Picotee, and Pastel Mix.
2. Soak corms before planting
Ranunculus are grown from claw-like ‘corms’ — a swollen underground plant stem that stores the nutrients for the plant until needed. Look for large corms as they have more stored energy and will grow larger and have more blooms.
Soak the corms in tepid water for 3 to 4 hours (not longer). The corms will absorb the moisture and often double in size.
3. Plant ranunculus correctly
Plant corms 2-3 inches deep and about 6 inches apart. Place ranunculus corms in the ground with the claws facing down. Fill the hole back in with soil and water well. Do not water again until sprouts appear above ground.
For square foot gardening, plant four corms per square foot.
4. Care for growing ranunculus
Overall, ranunculus is an easy plant to grow and is pest and disease-resistant.
Ranunculus needs plenty of sunlight to grow well. Ranunculus grows best in moist soil but does not like overwatering. If soil is not well-draining, ranunculus corms often rot.
SPECIAL NOTE: All parts of ranunculus are poisonous when ingested. The plant sap may cause skin irritation. Poison is not residual in the soil; only the plant is poisonous.
5. Enjoy ranunculus blooms
Corms planted in the fall typically bloom for about six weeks. Spring-planted corms bloom for about four weeks, depending on the weather. Once temperatures heat up, the blooms will stop.
For the longest vase life (10-12 days!) harvest when buds are colored and “squishy like a marshmallow” but not yet open. If they are harvested after opening the blooms last about a week. Use a floral preservative to encourage long vase life.
Deadheading plants encourage more blooms.
When blooms finish and the leaves begin to yellow and die back, cut the foliage off and stop watering. Allow the corms to dry out and go dormant. If desired, dig up dormant corms and store them in a cool, dry place until it is time to plant next season.
When growing ranunculus for cut flowers it is best to treat it as an annual and plant new corms each year.