How to grow ranunculus
One question I am asked frequently is, “What do flower farmers do over the winter?” Winter is indeed a time devoid of fresh flowers for most small scale farmers / farmer florists. However, in addition to catching up with all the record keeping, administrative tasks, and projects reserved for frozen ground days, there’s a flurry of activity behind the scenes laying groundwork, planting and planning for next season’s blooms! One of the stars of early spring I always grow are specialty varieties of Ranunculus asiaticus. These gorgeous flowers enjoy cooler temperatures but corms can never freeze. Growers in zone 6b like myself will have the most success planting in a protected environment during the fall, with additional successions into late winter. High tunnels are optimal, but low tunnels can provide adequate protection with agribon and/or plastic. Though there are no fresh flowers to be harvested in unheated structures, daily work is happening over the winter to grow our beloved spring flowers.
About ranunculus:
These ruffled beauties are oftentimes referred to as the “rose of spring.” Ranunculus are very popular star focals in bridal bouquets and other wedding florals, as well as Mother’s Day flowers.
Ranunculus are one of the most desirable cut flowers I grow. There are numerous series of ranunculus available, how do they compare? I have found that the Amandine series is slightly more heat tolerant than LaBelle. Half-clone and cloned varieties have larger flowers. Tecolote tend to be more single or semi double and smaller in size so not on my grow list, except for Tecolote Cafe which is an exquisite color mix of russet/golden tones. However, my favorite to grow are the exclusive Italian varieties: Cloni Success, Elegance and Cloni Pon Pon. The colors are just extraordinary, the blooms are generally larger in size and stem strength is excellent. I will be trying the Romance series this season.
However, being so very coveted by growers and high-end floral designers, not only are the Italian corms difficult to obtain, these varieties are the most expensive on the market. They are a true luxury bloom for the discerning buyer who wants the best!
How to grow ranunculus (in a nutshell):
Ranunculus can be a bit finicky. They prefer cooler temperatures and begin to enter dormancy when thermometer readings climb consistently over 75F. Therefore being located just north of Philadelphia in USDA hardiness zone 6b, I have the best success planting under protection in fall, with a few successions until late winter.
Start with ranunculus corms and presprout prior to planting. Soak in tepid, oxygenated water for 3-4 hours. I prefer to use an inexpensive fish tank bubbler rather than letting the water run slowly over the container. Then soak in water treated with Rootshield for 30 minutes to help prevent rot.
Cover soaked corms in a couple inches of barely moist vermiculite (or potting mix), “legs” down, then let rest for about 2 weeks at 50-60F to presprout. Check periodically for rotted corms and remove immediately if found.
When roots and baby shoots appear, it’s time to get them planted in their growing spots; plant 1” deep measured from the crown. Make sure the area has good drainage, take care not to overwater and ventilate on sunny days. Good air flow is critical for healthy plants! Scout regularly for pest damage and treat accordingly. Your future self will thank you if you are proactive!
Be aware of calcium levels in your soil as deficiencies may lead to stem issues like splitting and bending. Protect from freezing temperatures with layer(s) of row cover as the plants are not frost hardy. Best blooms in full sun in my area.
You will be rewarded with jaw droppingly beautiful flowers featuring delicately textured, ruffled petals and excellent vase life!
Ranunculus in a mix of salmon, peach, pink and rose tones.
Incredible jewel tones and luminescent quality of Italian ranunculus Cloni Success Sherry.
.
