*Looking for a quick ranunculus review? Scroll down to the end.*
Ranunculus are one of our most popular spring flowers. When I first started growing flowers in Oklahoma, I thought there was no way I could grow these delicate looking blooms in such a harsh environment. But over the years I've grown hundreds and every year I'm amazed at how incredible these flowers are. Resembling a smaller version of a peony, ranunculus last well over a week in the vase and come in all colors from white, blush, salmon, yellows, to bright pinks, oranges, and reds. With just a bit of extra work on the front end, you will be so glad you grew these blooms come spring time.
Ranunculus are grown from 'corms,' which is a type of bulb. They resemble a little octopus and are surprisingly small and underwhelming. Don't let these little corms fool you, because they have everything required to produce incredible, florist quality blooms in your own backyard!
Ranunculus will produce 5-7 stems per plant when continuously cut and watered. They usually bloom for me between April-early June. They do not like our heat and will slow down production when temperatures reach >75F. I prefer to grow them in an unheated hoophouse, but they do great for Terri in Claremore, OK in the field. My primary reason for growing in the hoophouse is for wind protection come spring, rather than cold protection in the winter.
Prior to planting your ranunculus, you will need to soak them for best results. Soak corms in a bucket for 3-4 hours in room temp water. You can use a fish aerator to keep oxygen in the water or drip water into the bucket by letting your faucet drip slowly. Don’t oversoak or they will rot. I always set my timer for 3 hours, just in case. After soaking, you can either plant directly into the ground (tentacle side down) or presprout in a tray. I have had the best results by presprouting in a tray, as I'm allowed to control the temperature and moisture better in the tray. However, if you don't have the materials, space, or time, don't stress about it and just plant the corms directly into the ground as described below.
To presprout, fill a 72-count seed tray half full of moist (not soaking) potting soil.Cover corms with soil, cover with a dome and leave the tray in a cool/dark place for 10 days. Check every few days to make sure the soil is moist, but not saturated. If you notice mold forming on the top, remove the dome and replace molded soil and any corms that feel squishy (those corms have rotted). You will notice roots starting to grown from the bottom. Once sprouts start coming out of the top of the soil, you can move them under a led shop light until you have your first set of leaves. Don't forget to 'harden off' the ranunculus prior to planting outside. You can do this by slowly increasing the time they are outside. Start about 1-2 hours/day in a protected location, then increase by a couple hours a day. Do not leave them outside in the tray in freezing temperatures. After about a week, they will be ready to plant outside.
s can be fall planted in Oklahoma zone 7b and surrounding areas. I will usually succession plant in order to extend my harvest season. I plant my first succession around Nov 1, then continue every 1-2 months until Feb 1. Choose a garden area in full sun to part sun, ideally with some wind protection. Till the bed or remove weeds according to your preference. Amend the beds with generous amounts of compost (ideally about 2-3 inches) and a balanced organic fertilizer or a 10-20-10 fertilizer. Mix in well. Plant your ranunculus corms or transplants about 9-12 inches apart. Plant with the 'tentacles' facing down, about 2 inches deep. Ranunculus are susceptible to fungal diseases, so increasing your plant spacing will assist with air circulation and hopefully yield less fungal pressure. Water your corms in well, but try to avoid letting your corms sit in water, as they can rot. I utilize a drip tape system, with a dripline going down each line of ranunculus. You want to maintain damp soil throughout the season.
When temperatures are forecasted below freezing it is necessary cover the plants with frost cloth or a blanket. If they are exposed to ground temps below 25F, they will freeze then rot. I will often keep a frost cloth over my ranunculus after first planting them out to prevent damage from cold and pests. As temperatures warm up in the spring, the frost cloth only goes on the plants when it is freezing, as the plants are usually large enough to withstand some bunny nibbles. Ranunculus do best with wind protection, whether you have a protected location in your garden or choose to use hortonova netting to prevent damage on those crazy spring days.
Your plants will be slow to grow during the fall/winter and put on a good bit of growth in early spring. You will begin to see stems growing and the ranunculus are ready to be cut when they are in 'marshmallow' form. Basically, when the bloom resembles a marshmallow and can be slightly squished, you can cut at the base of the stem. Place in cool, clean water and enjoy for days.
*If you notice yellowing/brown/wilted damage to the foliage or suspect fungal issues, you may consider removing the damaged foliage and spraying an antifungal such as copper or cease. If I have cease available at time of planting, I will spray the transplants and soil as a preventative and keep an eye for damage throughout the season. Other pests that may arise include thrips and aphids. These can be treated organically with spinosad or with the use of beneficial insects such as lady bugs or green lacewings which can be purchased online or at local garden centers.
There are several varieties of ranunculus to grow. Our favorite varieties include Amandine, LaBelle, and various clones. All of the ranunculus varieties in our shop have been proven on our Oklahoma farms with great results. You can find our availability here.
We hope this is helpful and that you have great success growing ranunculus this spring! It is a truly magical flower that will wow your friends and family and sure to liven up your home for weeks!