Seeing beautiful spring bouquets of Ranunculus and Tulips for sale each year got me wondering if I could have those blooms as early as April or May in my garden. A grower living very close by sells her gorgeous bouquets at our local farmer’s market in the spring and made me envious enough to try.

Tulips are easy but Ranunculus not so much. Although the brightly coloured flowers of the Ranunculus variety I am writing about, belong to the same family as the common yellow buttercup, these flowers are more tricky to grow in this climate. They grow from small octopus-shaped looking corms that must be planted in spring and retrieved in the fall. They will not survive our harsh winter in the ground. In reading about cultivation of these more luxury cut flowers I realised the process needed to be started as early as January to achieve early bloom. What I didn’t know is that a heated greenhouse can advance the process substantially. This is how our local grower is able to provide these wonderful bouquets so early. However I have an unheated south facing greenhouse so I decided it was worth a try.

I started the corms indoors in early March rather than January. By starting, I mean getting them to sprout. I had purchased the shrivelled up little corms in October so they need to be rehydrated. After soaking the corms overnight in water, I lay the corms on some dampened potting mix in a shallow tray and placed in a north facing window. The plumped up corms sprouted very quickly and once I could see healthy roots, I potted them up. These healthy looking little plants were kept in a cooler north facing window for a few weeks and then placed in a south facing window where there was more warmth and light.

By mid April I felt the risk of below freezing temperatures in the greenhouse was low enough that the plants could be put out there. I planted three up into a large pot and kept the remaining ones in their small starter pots for planting out into the garden once nighttime temperatures were consistently above freezing. That was a longer wait than I had hoped for and the plants did not get out into the garden until the beginning of May. The young plants grew slowly but happily until late May, early June , when I started to see the flower buds appearing. Those kept in the greenhouse bloomed about two weeks prior to the garden planted ones.

My goal of having these blooms by May did not work but I certainly enjoyed them in early June. Whether starting them in January in the house might work I don’t know. Ranunculus can withstand one or two degrees of frost so it might be possible to have them in my unheated greenhouse sooner. Certainly any commercial grower in this climate must provide supplemental heat in order to achieve early spring bloom. The catch is that Ranunculus prefer cool temperatures so too much warmth would not be a good thing.

left: earlier blooming pot now wheeled out to patio.

above: garden planted Ranunculus

I have not decided whether the process is worth the coveted bloom but I have some corms now, so they most certainly will be lifted and likely will go though another cycle next spring albeit with an earlier start. I would love to hear from others about growing Ranunculus.