I started growing hardy Cyclamen in 2010, with a plant of C hederifolium from Beaver Creek and seeds of C hederifolium and C coum from a specialist grower in the UK. The plant is indoors for the winter now, along with several of the seedlings, some of which have grown into big, flowering, four-year-olds. A few of the seedlings are outdoors under the snow, frozen in the ground or in containers. Two are enduring their third winter, another its second. Does this mean C hederifolium, rated hardy to zone 5, is hardy in zone 3? Generally, no. My survivors are three out of a few dozen. I think it’s fair to say that C hederifolium may be hardy in an urban zone 3 garden under heavy protection (dry leaves + snow) during an average or relatively mild winter.
Last fall (2013), I left five C hederifolium outdoors: two newly transplanted into the alpine pan; one already established in an alpine trough; one newly transplanted in the peat bed (after surviving the previous winter in the open garden); and one in the open garden, in a lightly shaded bed of Primulas under an apple tree, where it had survived one winter already.
This spring (2014), two of the five appeared to be alive. A third one raised a single leaf in October. The other two showed no signs of life above ground.
Of the two in the alpine pan (pictured here last fall), all leaves but one had frozen dead, and that one lasted only a short while into the spring. Through most of the spring and summer, the only visible remnant was a seed pod on a spiralled stem.
But the stem and the pod remained firm, indicating a live corm attached. Eventually the seeds ripened, and I collected them; from then, there was no sign of the plant. But late in September, leaves and flower buds began to rise — over a dozen leaves and four or five buds.
The leaves of C hederifolium are frost hardy, but the flowers are not (inconvenient in a fall-blooming species). Only one bud managed to open.
Next year, I will have to move the pan in September to a sheltered spot near the house.
Of the three plants that had already survived one winter, the one that had been moved to the peat bed showed only a single firm, green leaf, and it soon died. The plant under the apple tree had two or three living leaves, and produced more, along with a few deep pink flowers, late in the summer.
The plant in the alpine trough seemed to have died — there was no sign of it, until it put up a single leaf in October.
If that leaf is alive in the spring (quite likely, I think, as it is a young leaf), it may feed the corm through the summer, and the corm will then give rise to many new leaves in the fall.
Last December, I started more seeds, my own and several varieties acquired from the Alpine Garden Club of British Columbia‘s seed exchange. While I was painstakingly raising new seedlings, one of my plants raised its own.
This winter I want to try another reputedly hardy species, C purpurescens. I will also start the seeds collected from the C hederifolium in the alpine pan, hoping the offspring will be as hardy as the parent.