Updated: Nov 4, 2022
Last year was our first season growing large numbers of anemones and ranunculus in our large high tunnel. We planted in the fall of 2020 and they grew over the winter and we were so happy with how the plants and flowers grew! It was a commitment as we had to go out and cover them with frost cloth (sometimes double cloth) every single night of the entire winter and right on through the whole month of April, but it was absolutely worth it.
The little nubbins that ranunculus and anemones grow from are corms, although many people call them bulbs, and that's ok, as long as we all know what we are talking about. Anemone corms nubbins are the ugliest little gnarled things and believing that they will produce gorgeous flowers is a true act of faith. Similarly, the ranunculus corms are like something you might accidentally sweep up and throw in the trash if you didn't know better, yet they are the most precious of garden treasures.
Last year we planted in October and had hoped to back that up a few weeks to see if we could move our production up a to meet the Valentine's Day demands, but we were so busy with our long productive fall that we didn’t get many planted early. Add to that the very cold days we’ve had since late December and I don't know if it will work or not, but certainly hope so. In 2021 the very first anemone flowers appeared by early February, but the rush of flowers did not begin until late February and early March and they continued right through May. This year we’ve had occasional flowers since October, with enough to make a bouquet in December—these coming from corms that we missed when we dug them in the spring. They stayed dormant in the high tunnel soil all summer until it cooled down and they were ready to grow again in the fall.
I have a useful textbook on flower production (Floriculture by Dole and Wilkins) which says that fall planted anemones will flower for 10 weeks, while winter/spring planted corms only flower for 4 weeks--this alone is a reason to plant in the fall whenever possible. However, that ten week period does end and it should be said that the late winter/spring planted corms take us farther into spring, as they flower later. So a combination of the two planting times is ideal.
We soaked our corms in slightly running water--this involves multiple small buckets stacked in our kitchen sink with the faucet dripping for 8 hours. Soaking hundreds of corms required several days. My family were ready to have the buckets out of the house, but if someone helps me to install the sink in the workshop it will never happen again. Just saying.
I've read that some growers soak their anemones a shorter time than their ranunculus, but honestly, I soaked them all for the same amount of time and had essentially no loss of corms. The only significant loss I had were Salmon cloni, which I'm guessing is related to the variety, not the way they were grown, but who knows--this was not a scientific experiment.
I find the best way to keep track of different varieties in planting is to put them in the yellow plastic mesh bags that bulbs come in with the name written on a plastic plant tag. This way I cannot lose track of which corms are which. Be prepared, the ranunculus will expand tremendously, so leave room for this! The anemones swell up, but not as dramatically as the ranunculus.
After soaking in the slightly running water it's time for the corms to go into crates with soilless mix to pre-sprout before they are planted into the ground. I use tulip bulbs crates, which many will recognize as vegetable crates that they see at farmers markets. If you can get your hands on these consider yourself lucky. Every flower farmer on earth is looking for a stash of them and they are in short supply. If you have a stash of them please contact me! I will gladly take them off your hands in trade for flowers or money. :)
According to academic researchers who have taken the time to measure this kind of thing, pre-sprouting your corms will give you more flowers. I cannot explain this, I can only report the results. But I pre-sprout all of my corms.
Pre-sprouting takes a few weeks and during this time the crates can be stacked in a cool dark place, but they need to be protected from frost. You should check on them regularly and when you see signs of life—sprouts and roots—it’s time to get them in the ground.
Perfectly pre-sprouted ranunculus ready to plant.
We have two large high tunnels and this is where we plant these little babies. They like soil without covering on it (no landscape fabric) and we crowd them in fairly closely, spaced at about six inches, or even a little less.
All through November and December the plants grow their beautiful tender little leaves and look very delicate. We put wire hoops over the plants about five feet apart and cover them with heavy frost cloth. Sometimes the frost cloth stays on during the day if temperatures are very, very low, but generally we push it off to one side each morning. Even on a cold day the high tunnel can easily get into the 70s when the sun shines and the plants can cook if they are covered or the sides aren’t opened a little.
When the plants start to actively grow it’s time to start watching for fungus. Remove all yellow leaves and any that have visible fungus growing on them and take them out of the high tunnel immediately. Do not compost. This will help to prevent problems from spreading from plant to plant or onto your farm or garden. Do not over water. These are plants that can live on the dry side. I find that I water about once a month in the cold months of winter and follow advice I was given not to water if the temperature will fall below 25F in the next few days. This takes a lot of weather watching, but that’s what it takes to grow these beauties in a cold climate. :)
Spring is coming…