Bulletin of the American Rock Garden Society Volume 50 Number 4 Fall 1992 Cover: Gentiana paradoxa by Rob Proctor of Denver, Colorado Bulletin of the American Rock Garden Society Volume 50 Number 4 Fall 1992 Features Sorting out the Gentians, by Geoffrey Charlesworth 243 Fritillaries of Central Asia, by Josef Slegl 253 Trillium Rescue, by Don L. Jacobs 261 The Story of Fritillaria 'Martha Roderick', by W.H. de Goede 264 New Home for Rock Plants, by Elisabeth Sheldon 265 Eriogonums: Secret of the Dry Garden, by Irma Gourley 271 Preserving Rock Garden Specimens, by Karen Matthews 275 Spontaneity on the Rocks, by Panayoti Kelaidis 285 The Arctic Harebell, by J.S. DeSanto 291 Hunting for Red Helleborus niger, by Will McLewin 295 Departments Plant Portrait: Gentiana paradoxa 276 Awards 299 Books 305 Gentiana algida 242 Bulletin of the American Rock Garden Society Vol. 50(4) Sorting out the Gentians by Geoffrey Charlesworth 1 here are some genera in which tors. It is one of the hallmarks of a many of the species are considered good grower if a large patch can be good alpine plants. Androsace is such produced and maintained year after a genus, and we tend to dismiss the year, but the despair of most of us, who species that are not up to the highest have only occasionally seen a few small standard as not worth growing—for plants in our own gardens and then not instance, A. loctiflora or A. albana. It always with the astonishing color we is a mistake to make such odious associate with the species. So try comparisons of species within a genus. comparing G. tibetica with, for Instead, we should look at a plant for its instance, Trillium luteum. It may not own sake, assess its beauty and proper• win this beauty competition either, but ties, and ask whether we can use it in there is a fairer comparison to be our gardens. observed. Both have that faded yellow, A genus with a great variety of old paper look, and both depend on species is Gentiana. It contains a wide leaves for their garden effect. They fill range of architectural form, color inten• just about the same niche in a slightly sity, and garden usefulness. Think of shady area—that is if you start with a Gentiana tibetica: every reference nice clump of the trillium. A small describes it as "ugly," "rubbish," "not garden would probably prefer Trillium worth growing," and other epithets too grandiflorum and Gentiana scabra, numerous to list. Think of Gentiana but an imaginative gardener with verna: everybody sighs at the intensely enough space can easily accommodate blue darling of early spring. Poor G. the other two. tibetica doesn't get a chance when When reading Wilkie or Clay or compared with G. verna, because there Farrer or Bartlett on gentians, put what is. no comparison, and none should be they have to say in context, and grow a made. Gentiana verna is a difficult, plant yourself before you make up your capricious plant that is totally unreliable mind about its beauty and its usefulness. from one year to the next. It wins You may still end up calling G. tibetica prizes in shows and accolades from visi• rubbish or at least not allowing it in your 243 own garden, but one day you may see it The Best planted where whatever beauty it has is My first group is the "best" group. revealed, and you could be forced to Here are the difficult beautiful plants concede that you misjudged. that would probably not last many years Gentians have been classified by outside. These need alpine house treat• botanists into sections of related ment to grow well, and if you can't species, but because grouping them provide this, you have to find exactly according to garden use might also be the right spot in the garden. Try grow• of some value, I am going to proceed ing them from seed. You will need with my own classification. You can dig many plants to achieve even moderate out the standard botanical treatments success with a few. Buying plants is for yourself by reading the above frustrating—and they are not easy to authors and, of course, the Harkness find to begin with. Seedlist. You could also make your The Gentiana verna types flower in own classification; have a lot of fun on April to May. Gentiana verna itself has a rainy day if you want to try pulling many geographic races which are mine apart by re-aligning a few species sometimes given specific names here and there. I won't limit myself to (photos, pp. 278-279). The best G. species I have actually tried to grow; verna has very fine blue flowers about other authorities may not have grown half the dimensions of the familiar G. these species either, but their descrip• acaulis and is perhaps not so intense a tions are fairly convincing, and you can color even at its best. There are less judge for yourself after reading them. good blues, too, but none is to be The flower of a gentian is essentially rejected. This species forms ground- a trumpet, the corolla being a tube that hugging mats that can be pulled apart flares out and divides most often into after flowering when they get sufficient• five lobes (fours and sixes are possible). ly large (the second year maybe). The Some gentians have petals fringed at pieces will have enough root to pot up the margins. Between the petals there and ought to be large enough to plant may be connecting "petals" called out by September. I have tried this divi• plicae. These may consist of one tiny sion in a very peaty compost in a plas• point, a double point, or a whole fringe tic pot, and the propagated plants did of points—or be nonexistent. If this quite well. In the same mix outdoors, I feature is prominent, it adds richness of was less successful. In a sandy soil, G. form and texture. In some species there acaulis also flowered but sulked and are stripings and spottings that are also failed to increase. Mary Bartlett insists interesting close-up. At a distance too that this species is a lime-lover, but I much artwork tends to diminish the have never given it added lime or impact. The calyx can also be sculpted grown it on tufa, so you may want to with ridges and divisions, but this is not experiment in that direction. The corol• a feature for which you would grow a la is a moderately long tube sitting in a plant. Sometimes the trumpet does not green-ribbed calyx, its five petals open• flare but closes at the end, giving an ing to a star with a white center. Some effect like a balloon. Comparing this geographical variants are G. balcanica with a Platycodon in its early stages, (a brilliant, greenish-blue outside, we expect this to open, but in the case endemic to the Balkan Mountains); G. of the bottle gentians, the flower pontica (wider, dark green leaves, large remains with only a tiny opening for flowers); and G. sibirica (tiny). pollinators. Gentiana angulosa or G. verna v. 244 Bulletin of the American Rock Garden Society Vol. 50(4) angulosa (=G. tergestina or G. verna of tiny rosettes. It wants lime and ssp. tergestina?, dark blue, photo, p. blooms in July. Its subspecies schle- 278) is a bit larger and taller with icheri forms dense tufts and may be the lighter blue flowers and longer leaves tiniest of the verna group. Gentiana and wings along the calyx tube. froelichii, the Karawanken gentian, Gentiana oschtenica, from the Cauca• bears sky blue flowers in August and is sus, is a yellow-flowered species close "an aristocratic blue frigida" without to G. verna (photo, p. 279). In Czecho• the streaks on the flowers (see G. frigi• slovakia it is grown by a few experts, da below, under the non-blue gentians). and it is a real prize winner. It is from the Julian Alps. Other species belonging to the aristo• cratic group of gentians are also worth Gentiana acaulis and Relatives growing in a container, and they need These are the gentians you think of extreme care. Gentiana bavarica, with when you think of gentian blue. Only deep blue trumpets and tiny rosettes of slightly less beautiful than the G. verna light green, spatulate leaves, grows in group (or slightly more?), they are wet areas in nature. It has a subspecies bigger plants with enormous trumpets subacaulis, the dwarf Bavarian gentian, and therefore less "alpine-looking," but which is a compact form with circular more showy (photos, p. 281). These leaves. Gentiana brachyphylla is a 2" are also spring gentians, but in my tight cushion with dumpy leathery garden flower a little later. My success is leaves; G. favratii (including G. orbicu- intermittent, so I will content myself laris) is closely related to G. brachy• with negative advice. Not deep shade, phylla with large, deep blue flowers not hot scree, not bog, not too lean a with rounded petals and tiny, oval, spat• soil. Try the edge of a border with rich ulate leaves, from the Pyrenees, Alps, soil or the shady side of a rock. If plants Turkey; G. pumila (a smaller G. verna heave and rot, improve the drainage. with narrow, lance-shaped leaves and There is a lot of speculation about the deep blue trumpets); G. pumila var. proper acidity of the soil. This may be delphinensis has blunt petal lobes and a important if you live in a region with different calyx; G.