When I first saw the gorgeous blooms on ranunculus flowers, I didn’t think it was possible to grow them here in the low desert of Arizona. 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. Learn how to grow ranunculus (even if you live in a hot summer climate like the low desert of Arizona) with these 5 tips.
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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 7 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 danger of frost is passed.
In the low desert of Arizona, plant ranunculus corms from October – November and again from February – March.
- October 24
- November 16
- November 30
- January 23
- March 5
- March 26
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 4 corms per square foot.
4. Care for growing ranunculus
Overall, ranunculus is an easy plant to grow and it’s fairly 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 6 weeks. Spring-planted corms bloom for about 4 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.
Deadheading plants encourages more blooms. For cut flowers, cut stems just before buds open for the longest vase life.
When blooms finish and the leaves begin to yellow and die back, cut foliage off and stop watering. Allow the corms to dry out and go dormant. If desired, dig up dormant corms and store in a cool, dry place until it is time to plant next season.
eva
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.
eva
Thursday 10th of February 2022
@Angela Judd, Wonderful. Thank you.
Angela Judd
Thursday 10th of February 2022
The planting mix already has compost so you are good to go! Happy planting!
Jen
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 ?
Angela Judd
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.
Leslie
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.
Angela Judd
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.
Mae
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?
Angela Judd
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.
Teresa Horler
Wednesday 20th of October 2021
do you soak them before or after refrigerating?
Angela Judd
Friday 22nd of October 2021
Soak them just before planting.