(This article was originally published on August 29, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions and commnts.)
Most gardeners have never heard of the genus Cremanthodium. They are a group of rather obscure composites that hail from the Himalayas. I was first introduced to them when our local rock garden society hosted a guest speaker named Finn Haugli, the Director from the Tromsö Botanical Garden in Norway. That botanical garden is located well above the Arctic circle. I found it hard to imagine much of anything growing there but was I wrong! They are located in a zone 4! It is dark for 3 months of the year and snow is generally plentiful. However, it is light for 24 hours a day in summer and despite summer temperatures that rarely rise above 70 F, they grow an amazing assortment of plants, especially bulbs and Himalayan alpines. The speaker showed us South American Peruvian lilies and Oxalis, Turkish Fritillaria, drifts of Himalayan blue poppies, Grecian Ramonda and Haberlea...and the list of choice alpines goes on. All were growing in the open despite several being rated hardy only to zone 6! As it happens, in Tromsö, snow comes early and stays late. The soil rarely freezes and by the time the snow melts in spring, the temperatures rarely drop below freezing. For these plants, winter is like being placed in a refrigerator; nothing like a zone 4 winter in the US mid-west!
However, I digress. During the presentation, we were shown this very unusual and exquisite yellow daisy called Cremanthodium (no common name). The interesting feature of this plant is that their flowers are nodding. Superficially they look like a nodding form of a leopard's-bane. I immediately fell in love with this alpine ‘odd-ball' (but then I do have a fancy for unusual plants!). I immediately started a search for this genus. Gee, was I in for trail.
First, I'll give you more information on the genus. Cremanthodium are native to sunny or lightly shaded, alpine regions of Nepal, China and Tibet. There are about 50 species in total but only a handful are ‘common' (I use that termed loosely) in cultivation. Plants produce a basal rosette of leaves and flower stems that rise 30-45 cm, ending in a medium-sized, nodding yellow daisy. They are delightfully fragrant. There are several reasons that Cremanthodium are not more popular. First, they need cool summer temperatures. Hence, their luxuriant growth at the Tromsö Botanical Garden. They also need evenly moist soil. The require an even snow cover in winter and barring that, will need a thick mulch to help them through the winter. They detest wet, soggy winters. All these growing requirements seriously narrows the regions where they can be successfully cultivated. Gardeners in higher elevations of the Appalachians, Atlantic Canada, drier areas of the Pacific Northwest and higher elevations of western North America have the best chance. They seem to do better in Europe as a whole, especially Scandinavian countries, Iceland, northern Scotland and higher elevations of the Alps.
I started my search for this genus by checking our mail-order alpine nurseries in Canada and the USA. No luck! Then I checked some of the seed exchanges of local alpine societies...again no luck. As luck should have it, I work at a botanical garden and we have access to European botanical garden seed exchanges. I was lucky enough to find three Cremanthodium species offered by the Reykjavik Botanical Garden in Iceland. I placed my order and waited. Ten weeks later the seeds arrived (along with a bunch of other choice alpine species!). I sowed the seeds and waited. About 2 weeks later, the first germinated...then another. A hopeful sign. A few days later a seedling sprouted from another species. And that was it. Two plants from C. arnicoides and one from C. delavayi. I found out later that Cremanthodium require fresh seeds to get maximum viability. The seeds I sowed were probably several moths old, hence the poor germination. I coddled the three seedlings along and planted them out in our botanical garden's rock garden, where they were promptly eaten by slugs. I thought the story would end there. Next spring I was amazed to see the Cremanthodium sending up new leaves. I immediately placed a ring of slug bait around them...and continued to do this all summer! Summer passed into winter and another spring. The third summer, which was 2008, I was amazed to see C. arnicoides send up a flower stem. On July 17 the bloom opened. I was delighted! I hand pollinated the flower to get maximum seed set, then sowed the seeds as soon as they were ripe in the fall. This past winter 2009, the Reykjavik Botanical Garden once more offered Cremanthodium seeds. This year they had C. helianthus and C. ellisii. At the time of writing this article, the first seedlings of C. ellisii were sprouting. The fresh seeds of C. arnicoides gathered last summer were stratified all winter in our root cellar and have just been brought into the heat. Time will tell if I get a bumper crop of seedlings!
Front and side view of my first-blooming Cremanthodium arnicoides
So the moral of the story is that perseverance pays off. I hope to find more Cremanthodium species in the coming years. Our cool local summers seem to be ideal for this genus. Now, if only I could have as much luck with Himalayan blue poppies! So far I have only Meconopsis betonicifolia and I'm currently looking for more.....but that's another story!
I would like to thank Peter Korn for his picture of a Cremanthodium species in this garden in Sweden (upper right), Antyram for his picture of C. nepaulense (middle left) and the Station Alpine Joseph Fourier for use of their picture of C. ellisii (middle right).