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.
In the low desert of Arizona, plant ranunculus corms from October to November and again from February to March (Presprout corms if planting in February – March)
Floret’s top choices for ranunculus varieties are the La Belle Series which includes Salmon, Champagne, Orange, Pink Picotee, and Pastel Mix.
Flowers to Plant Outside & Seeds to Start Indoors Each Month in the Low Desert of Arizona.
• PLANTING GUIDE: Each month lists annual flowers and bulbs to plant outside & seeds to start indoors.
• BLOOMING GUIDE: Photos show what may be in bloom that month.
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
Ranunculus grows best in rich, healthy, well-draining soil with plenty of sunlight. Add several inches of compost and a balanced organic fertilizer to the soil before planting.
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.
In the low desert of Arizona, you can expect blooms to begin in February for fall-planted corms and continue through May for spring-planted corms.
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.
Learn more about growing your own cut flowers in this blog post about making flower arrangements from the garden.
Visual planting guides for vegetables, herbs, fruits, flowers & vines.
Tuesday 2nd of May 2023
Hi, do I have to dig up the corms or will they rebloom again next year on their own. My freesia usually just rebloom without digging. Thank you for your advice
Tuesday 2nd of May 2023
You can leave them in the ground in many areas, and they will return. Summers where I live are often too hot, and mine don't return.
Wednesday 9th of February 2022
If planting in a pot (2 corms in a 12' pot), do I need to add compost? I'm local & am planning to purchase your special potting mix from AZ Worm Farm. :) Thanks again for all this excellent info.
Thursday 10th of February 2022
@Angela Judd, Wonderful. Thank you.
Thursday 10th of February 2022
The planting mix already has compost so you are good to go! Happy planting!
Wednesday 26th of January 2022
What do I do if my ranunculus leaves are turning yellow ? Planted in pots in October and they grew ok. Replanted out into a sunnier area but I’m not sure if it’s too much sun, too little nitrogen or soils is bad ?
Monday 31st of January 2022
Could be too much water. Container plants also need more fertilizing, so that could also be the problem. I would let them dry out a bit between watering and fertilize at your next watering with a fish emulsion dilution. Good soil in containers is crucial - hopefully you have a nice light potting mix in the containers.
Tuesday 14th of December 2021
Can I plant ranunculus corms in January? I live in Scottsdale and it seems like January and February have very similar weather.
Friday 17th of December 2021
Probably - January is typically our coldest month, so it may be a bit too cold for them and they may rot. But chances are it would be fine. The planting dates are guidelines, you can always use your best judgement.
Tuesday 9th of November 2021
Hello! Is it ok not to water the corms, even if the soil dries out before they sprout? And should I put mulch on top to help retain the soil's moisture?
Wednesday 10th of November 2021
It's best not to let the soil dry out completely. Adding mulch helps keep the moisture in the soil.