This large genus of Araceae comprises about 150 summer-growing, tuberous (or more accurately cormous) species and has become very fashionable in recent years. Although the majority of species grow in eastern Asia, their distribution extends to eastern North America and East Africa. Although there are many hardy species, there are also many tender ones from lower altitudes in subtropical zones. The problem with many recent introductions from China has been assessing their winter hardiness. We have been trying to assemble a wide range but a recent more severe winter has greatly depleted our expanding collection. Our problem was largely of our own making as we were growing them individually in containers to expedite identification. Many plants, by no means only those in the genus Arisaema, are perfectly hardy when growing in the ground, especially if they are covered by a substantial blanket of snow in winter, but are vulnerable when growing in containers, especially if a free- standing container becomes frozen. While the range of seeds we can make available at present is more limited than we had hoped for, we are still interested in this genus and are again working towards making an expanding range available.

The other problem in attempting to offer seeds from a wide range of species regularly is the unpredictable nature of seed-set. Individual plants of many species can be either male or female, so it is necessary to grow a reasonable number of clones (or at least plants) to ensure pollination. We make the qualification ‘plants’ as individuals can be male in one year and female in another. You may see a fine display of spathes but these are not going to result in seeds if they all conceal flowers of the same sex. Planting out a good-sized colony of each species, raised from seeds and in a suitable, protected environment, is the ideal but we are not yet at that stage of development in growing these.

As far as cultivation is concerned, these are mainly woodland plants, so, in general, a site in light shade with a rich but well-drained soil containing plenty of humus is needed. They will enjoy ample moisture when in active growth and drier conditions when dormant. Like some other Asian genera, such as Hosta, several species from eastern Asia grow particularly well in the climate of eastern North America, where they enjoy the high humidity of the warm summers and the cold of the winters. Mild, wet British winters are not always to their liking when dormant. Our main collaborator in Britain is our friend, aroid-enthusiast Mike Tucker in Somerset and we usually list some seeds from him, as well as from other growers.

Seeds can be sown from as soon as they are ripe in late summer until the following spring. The sooner they are sown the better. Germination should occur when the temperature reaches a sufficient level in spring. Some species can be sown in warmth under glass in midwinter, as for several other Sino-Himalayan genera, but we do not have sufficient knowledge of the requirements for each species to give anything but this very general indication of their needs. We shall leave the red pericarp on the seed if we can. This should be removed before sowing but read our comments under the genus Arum regarding this.

Nomenclature and further information : The genus Arisaema has not yet been covered for ‘Flora of China’ so we cannot adopt a standard nomenclature based on an account in this ongoing project. There are, however, two books on this genus. ‘Himalayan Cobra Lilies’ by Udai C. Pradhan (1990) covers the 24 Himalayan species. The more recently published ‘The Genus Arisaema’ by Guy and Liliane Gusman (2002) attempts to cover the entire genus. The Gusmans are generally acknowledged to be the world authorities on this genus and their book will no doubt remain the standard work. Several aroid-enthusiasts, who know much more about this genus than we do, have been rather disappointed with it, particularly with the photographs in it. This is a pity as Arisaema is a supremely photogenic genus.