ROCK GARDEN QUARTERLY VOLUME 58 NUMBER 1 WINTER 2000 COVER: Eriophorum scheuchzeri by Rhonda Williams, Wasilla, Alaska All Material Copyright © 2000 North American Rock Garden Society Printed by AgPress, 1531 Yuma Street, Manhattan, Kansas 66502 ROCK GARDEN QUARTERLY BULLETIN OF THE NORTH AMERICAN ROCK GARDEN SOCIETY VOLUME 58 NUMBER 1 WINTER 2000 FEATURES In Praise of Leafy Saxifrages, by Eva Gallagher 3 Alliums for Late Summer and Fall Bloom, by Mark McDonough 9 Those Interesting Vacciniums, by Arthur P. Dome 19 Thymes for the Rock Garden, by Rexford Talbert 35 The Pasayten Wilderness and Environs, by Coleman Leuthy 39 Exploring Southeastern Habitats for Rock Garden Plants, 47 by Rekha Morris Endemic Plants of the Olympic Mountains, by Carla Lankow 55 Sidetrips from Seattle, by Use Burch 57 Mount Rainier: Sunrise to Paradise, by Ruth Kirk 61 DEPARTMENTS Plant Portrait: Primula reidii 66 Musings: Watering 68 Book Reviews 70 Saxifraga x urbhim 'Variegata Aurea' gold spots on the leaves 2 ROCK GARDEN QUARTERLY VOL. 58(1) IN PRAISE OF LEAFY SAXIFRAGES by Eva Gallagher Once you start to get serious from seed, either from the exchanges about rock gardening you quickly or from specialist collectors. Although become familiar with that great alpine their flowers may not be as showy as family, the saxifrages. These include those from the better-known groups, the mossy types with their crowded they are all beautiful foliage plants, rosettes of multi-dissected leaves that and some of them are evergreen. The spread into bright green mats just an value of these plants increases expo• inch or so high. There are also the nentially once you realize that several encrusted types with strap-shaped are candidates for dry shade. leaves edged in white lime; these form The best known of the "leafies" stiff, leathery rosettes of various sizes. belong to the section Gymnoptera (as Representatives from both of these classified in the 1992 version of sections are readily available from Saxifrages—A Gardener's Guide to the nurseries and make great rock garden Genus, by Winton Harding). The four plants, as they are relatively easy to species and three main hybrids in this grow. Then there are the elite section are all endemic to Europe. species—members of the kabschia and These are all easy to grow with fleshy, engleria groups. These form tight, low loose, evergreen rosettes that throw hummocks of hard, often sharp-point• high panicles of red-speckled, white ed leaves and are valued for their flowers on scapes that can be up to 40 huge, short-stemmed flowers in hues cm high. They are indifferent as to soil of white, pink, or yellow. You have to type and will actually thrive in deep look to specialist nurseries for these, as shade. Like many of the saxifrages, they require harder-to-provide condi• this group hybridizes freely, so it is tions, such as a scree or trough. difficult to know if plants grown from But there are about a dozen more seed produced in cultivation are the sections in the genus Saxifraga, many real species. To add to the confusion, with choice species. It is some of these leaf shape can vary, and so many nurs• species that I lump into what I here call eries mislabel them. the leafy saxifrages. The only way to The most commonly grown plant obtain many of them is to grow them from this group is S. x urbium, the true 3 "London pride." It is unknown in the I bought was labeled S. 'Primuloides'. wild and is a very old hybrid of garden This is supposedly a more compact origin (S. umbrosa x S. spathularis). It form of the true S. urbium. After was first mentioned in 1697 in Britain. spending hours with a magnifying The common name has always glass and reference books, I have con• intrigued me, and I only recently cluded that it must be mislabeled. It learned of its origin. In the book, more closely matches the description Saxifrages, The Complete Cultivars and and picture of S. cuneifolia in Webb Hybrids, recently put out by the and Gornall. The leaves are a much Saxifrage Society, Martyn is quoted in darker green and are about one-sixth 1785: [The plant] "was formerly much the size of those of S. x urbium. They shown out at windows and balconies also have no hairs on the petiole, and in smoky towns, and hence with its the flowers have a yellowish-green being really beautiful had the names of ovary rather than a pink one. As well, London pride and none-so-pretty. the flower panicle on a greenish Other names used were St. Patrick's brown stem is rather sparse—all char• cabbage, pretty Nancy, prattling acteristics of S. cuneifolia. As this culti• Parnel, and prince's feather. Evidently var was distributed by a large whole• it was a great favorite during the early sale nursery there are probably a lot of Industrial Revolution! Unfortunately, it mislabeled plants out there. The true is often listed in books and nurseries as S. urbium var. primuloides has reddish S. umbrosa. (The true S. umbrosa is rare stems and lots of red speckles on the in cultivation and is native to the petals and pinkish ovaries. Selections Pyrenees.) Until recently, I have not S. urbium var. primuloides 'Clarence seen it in Ontario, although it is still a Elliot' and 'Walter Inwerson' sound common plant in Great Britain, where extremely attractive, both with 15-cm it is valued for its ability to grow in dry tall, red stems, and pink flowers that shade. The fact that some American perform best on a starvation diet. gardening books list its hardiness as Regrettably, they remain on my wish zone 6 or even 7 may have discouraged list. gardeners in eastern Canada. I have Saxifraga spathularis, seed of which I found it perfectly hardy, apart from a managed to get last year, has now tendency to winter burn if exposed to formed rosettes 3-5 cm across in a sun. Even then it recovers readily once shady peat bed. It looks to be a new growth begins in the spring. promising variation with longer-peti- I grew my London Pride from seed, oled leaves. Typically, seedlings in this and it seems to have come true, match• section take a year or more to get ing the description in A Manual of going and form full-sized rosettes. A Saxifrages, by Webb and Gornall. The natural hybrid, S. x geum (S. umbrosa x panicle of white flowers is tinged pink S. hirsuta, found in the Pyrenees) was due to the pink anthers, pink ovaries, also grown from seed and is again and red dots on the petals. It is spread• slightly different, with flowers stalks ing at a moderate rate in sandy, acid and flowers more strongly red-col• soil. I recently bought a cultivar, S. x ored. It does not seem to be doing too urbium 'Aureopunctata', which has well in a dry, shady crevice, but this smaller leaves that are splashed and could be as one of the parents is S. hir• dotted yellow, giving it a rather untidy suta, the one species in this group appearance. which really likes dampish conditions. Another very worthwhile plant that Species in this leathery-rosetted group 4 ROCK GARDEN QUARTERLY VOL. 58(1) Leaf Outlines of Saxifrages in Section Qamnopera a. Saxifraga hirsuta ssp. paucicrenata—hairs on leaves and stems b. S. hirsata ssp. hirsuta—hairs on leaves and stems c. S. x polita (S. hirsuta x S. spathularis)—just a few hairs on leaf d. S. spathularis e. S. x urbium f. S. umbrosa q. S. x geum (S. hirsuta x S. umbrosa)—just a few hairs on leaf h. S. cuneifolia ssp. cuneifolia i. h. S. cuneifolia ssp. robusta Modified from A Manual of Saxifrages, Webb & Gornall LEAFY SAXIFRAGES 5 that are still on my search list include pie-red spots on the petals. Both these the true S. urbium, S. hirsuta, and S. x plants are easy from seed, germinating polita (S. hirsuta x S. spathularis), the at warm temperatures. The third latter a natural hybrid found in species, S. coriifolia, though not very Ireland. different from S. rotundifolia, unfortu• All three species in the Section nately never seems to be offered in the Cotylea sound as if they would be exchanges. worthwhile to grow. All are evergreen Saxifraga granulata is the only and native to mountain woods in species of saxifrage that was consis• Europe and Asia. As they tend to tently so labeled by 16th and 17th cen• require more moisture than the tury botanists. As such, it is the type London pride group, they are a bit species for the genus—the species more difficult to please. Saxifraga around which the whole concept of rotundifolia has fleshy, rounded, the saxifrage genus gradually formed. coarsely-lobed leaves with characteris• It is a dainty plant with small, long- tic, long petioles. Flower stalks can be stalked, kidney-shaped leaves that are up to 50 cm high and are white, with thin-textured but hairy. The flower the typical, delicate red speckling. If scape can be up to 20 cm high, and the happy, it forms thick clumps. I have flowers are quite large and pure white another plant which is a more compact (rarely with red veins). This plant has version of S. rotundifolia, with thicker, a very widespread distribution in less serrated leaves. This thrives in Europe, being found in grassy mead• drier conditions, sometimes drying ows (the common name is meadow out, but recovering once moisture is saxifrage), as well as on dry, rocky again available.