Families of tiny alpines to be treasured

Press, 27 April 1984, Page 9

Families of tiny alpines to be treasured

A treasure which had to be accommodated in my rock garden during the autumn reshuffle is a clover, of all things. It’s a very special clover, a high alpine from the troubled area of the world which used to be known as Asia Minor. The name is Trifolium uniflorum, and the plant attached to it is a tiny tuft of ground-hugging clover leaves. To appreciate this plant you have to get down on your hands and knees and look at it through a lens. Instead of the usual round clover heads it has its flowers singly on short stalks. They are keeled, and no more than smm across. When you look closely at them you can see that they are exquisitely coloured in shades of pink and cream. Another variation on a familiar theme: in a genus largely comprising tiny and difficult treasures from the high mountains of Europe and the Himalaya, Androsace lanuginosa stands out as a tough, attractive, and impertubably easy customer which will fling itself over a rock or trail down a wall with abandon. Its silver-green foliage is attractive in all seasons, and in late spring and again at intervals throughout summer it smothers them beneath sprays of little, whitish, rosy-eyed flowers. If it has a fault this is that it is too vigorous to be trusted in proximity to smaller alpines; it has great smothering power. The variation, newly arrived from a mid-Canter-bury nursery and now safely tucked away at the side of the rock garden where it can trail to its heart’s content across a path, is A. lanuginosa sheriffii — Sheriffs variety, which has not previously been obtainable here.

The leaves look a little broader than those of the common form, and the growth habit is described as being more compact. The flowers are pink. Also new in androsace is A. villosa, which is at the resting stage now and has very woolly dormant rosettes. It somewhat resembles the more familiar A. sarmentosa, but forms more compact clumps. Whereas A. sarmentosa has bright rosy pink flowers, A. villosa has darkeyed white flowers. I have planted it in my extended rock garden, along with the rescued remains of the choice A. halleri, a tinyleaved Swiss alpine which, if happy, grows into a hedgehog-sized cushion studded in mid-spring with rosy pink, short-stemmed flowers. I had a fine specimen of this for several years, but grass grubs, or old age, or something else got into it during the summer, and it collapsed. Fortunately I managed to rescue a few pieces. This plant is probably just a

AxRDENER’S! W DIARY J Derrick Rooney

geographic form of the common European A. carnea, but it is a choice one. Its white-flowered equivalent is known as A. brigan-, tiaca, is a shade larger, and, considering the reputation of this section of the Androsace genus for difficulty, is almost embarrassingly easy to grow. This autumn seedlings have been coming up like mustard and cress around the parent in my rock garden. The plant grown in gardens as Gentiana acaulis was named by Linnaeus in the eighteenth century, but its origin is not documented. According to the available literature, there are no known wild populations in Europe which produce duplicates of the cultivated form. This isn’t necessarily disastrous, because the name

has become a sort of umbrella which encompasses a range of European mountain gentians, all largeflowered and all closely related. They differ only in fine details and in their choice of habitat. It’s a pity, in a way, that these spring gentiana have become known as “the acaulis group,” because “acaulis” is not a very appropriate name for them; it means “stemless,” and most of the plants in the group have flower stems ranging from scm to 10cm in length. Only Gentiana alpina, smallest of the group and a very distinctive plant with short, wide leaves and tubby, azure blue flowers, is truly stemless — and it is clearly a separate entity. I managed to obtain a tiny plant recently, and it is now sharing rock garden space with the androsaces. Gentiana acaulis itself has stems about scm long beneath its large, deep blue flowers, which are spotted green in the throat. It likes a bit of lime in the soil. Gentiana kochiana is similar, and is sometimes listed as a synonym, but it has more green spotting in

the throat, and it dislikes lime — its natural habitat is on igneous rocks. There is another important difference between kochiana and acaulis: whereas the shy flowering habits of acaulis have been the despair of generations of alpine gardeners, kochiana can usually be relied on to flower prolifically from an early age, and I hope for big things from the seedling I have just planted. If it is as true flowering as Gentiana angustifolia I will be happy. This member of the group has leaves which are longer and narrower than those of the others, but otherwise is very similar to acaulis, though perhaps a little more mois-ture-demanding. Perhaps more than the others, it appreciates a wet summer, and, when the season has suited it, will flower in autumn as well as spring. In my rock garden it has been flowering for several weeks. The flowers of angustifolia are a little tubbier and slightly shorter than those of acaulis and kochiana. The largest flowers in the group belong to G. clusii, which is unfortunately rarely obtainable. I know this plant only as a published description, which is of a plant with rough edges on its leaves and deep azure funnelshaped flowers with few or no green spots in the throat. Other names in this group which might appear in catalogues or seed lists include coerulea, dinarica, ligustica, occidentalis, grandiflora, latifolia, and maxima. The latter three are horticultural names only, and are presumably selections which have been named and propagated by British or Continental nurseries. I have not seen them offered in our local catalogue. Another of these horticultural forms, Gentiana ‘Coelestina,’ is obtainable in New Zealand, and I have just planted it in my new piece of rock garden. This has soft-coloured flowers which are just a shade or two darker than sky blue. A few weeks ago I saw an established clump flowering very freely in a Timaru garden.