A North Wales Alpine Gardener's Diary
This entry: May 2014 - Entry 21
Some easy alpines that hold their own among the be
There is a tendency when writing a garden diary to mention only the rarer or more unusual plants, but many of those that give the greatest pleasure, like the common birds that regularly visit our bird tables, tend not to be mentioned. These are the plants that anyone can grow with a modicum of skill and that are available from most alpine plant nurseries, and sometimes from garden centres. Here are a few of my favourites that bloom in May:
Rhodanthemum hosmariense AGM (Moroccan Daisy)
I have had this plant for many years, and seen it sold under a wide variety of names, including Leucanthemum hosmariense, Chrysanthemopsis hosmariense, Chrysanthemum hosmariense, and latterly Rhodanthemum hosmariense. Whatever the name, it has always been one of my favourite everyday plants and the only one in my mild garden that regularly bears some flowers 365 days of the year - some achievement, although in winter they are probably best removed as they tend to look 'tatty' and reduce one's appreciation of the beautiful sivery filigree foliage. It will grow anywhere that is not too shady or wet and looks lovely pouring itself over the edge of a large container or, as shown in the accompanying photograph, tumbling down the side of a wall. I say 'large' container because it is a vigorous grower, easily spreading to cover a square metre of ground in two or three seasons, but it is easily kept in check as it does not root down, and the pieces sheared off to keep it in bounds root with alacrity if placed in any gritty compost, or even directly in the ground.
Chiastophyllum oppositifolium AGM
This unattractive name does not do justice to this very attractive and extremely easy plant, which previously went the rounds under the more attractive pseudonyms Cotyledon oppositifolia or C. simplicifolia. It flowers for a long period through May and into June and if some of the seed heads are left on will generally seed around, though not in any aggressive way, as like most members of the succulent Crassulaceae it has quite a shallow root system. Being a semi-succulent plant it likes the same hot and dry conditions as the aforementioned Moroccan daisy.
Dianthus 'La Bourboule' and its form 'Alba'
Dianthus are favourite plants of mine, including such old border favourites as Sweet williams and various of the old laced pinks, which seemed to have a revival a few years ago but perhaps are now becoming less popular again. The alpine (or at least dwarf) members of the genus has always been popular with rock and alpine gardeners for a number of reasons, but perhaps especially for their perfume (not shared by all, though) and the fact that they carry on into late May-June where the earlier alpines leave off. If they have a weakness it is that as their common name implies, most have flowers in some shade of pink, though white selections are common, but somehow this doesn't seem to matter, especailly as pink goes so well with the silvery foliage common to many species. I grow quite a few species and may show you some of them in my June posting, but here we are dealing with easy, common plants, and the pink and white forms of D. 'La Bourboule' are just that. Put them anywhere in sun with well drained soil and they will gradually spread into nice flat mats, covered in early June with flowers that are attractive to insects as well as to alpine gardeners.
Helianthemums - flowers of the sun
Aptly named after the Greek sun god, Helios, the genus Helianthemum presents us with a range of very easy and colourful rock plants which flower for a long time from late spring into summer. I don't grow any of the many colourful hybrids and selections, not because I don't like them but because the space, even in my fairly large alpine garden, is too precious. But I do love our own native H. nummularium, which I photographed in full flower a few days ago on a local nature reserve near here, The same plant tends to be more vigorous in the garden, as the second picture shows. Perhaps a little more refined, being smaller in all its parts, is H. oelandicum subsp. alpestre from southern Europe, this will take a year or two to cover a patch of ground the size of a dinner plate.
Geranium cinereum 'Ballerina'
If you don't have this plant make it your business to get it, for it is one of the most beautiful reliable and long-flowering of alpines. The conditions it needs are the same as for the plants mentioned above and given sun and drainage it will live for many years and never give any trouble. Taxonomically it appears to be an intermediate between two subspecies, G. cinereum subsp. cinereum and G. cinereum subsp. subcaulescens, both excellent plants in their own right.
Silene maritima - Sea campion
Living here by the sea we have a number of cliff-dwelling native plants that justify their place in the alpine garden. One of them is Sea campion, which is a very good plant indeed, with largish pure white flowers displayed nicely on a mat of waxy silvery leaves. But beware its tendency to seed around a lot if the flower heads are not removed before the seed is ripe
Saxifraga 'Slack's Ruby Southside' AGM
There are many silver saxifrages at or just past their best now, but I thought I would show you just one, the AGM form of Saxifraga 'Soutside Seedling' from Slack Top Nursery in the Calder Valley. I know for certain that I have the right plant (there are a number of inferior forms about), because my plant was kindly given to me by the nursery's owners, Michael and Alison Mitchell. As you can see, it produces a wonderful froth of hundreds of small predominantly white flowers, each with distinctive red markings. Propagation is easy by detaching unflowered rosettes after flowering and pushing them into a very gritty rooting medium.
A couple of daphnes
As you will know by now if you are one of (the?!) regular reader(s) of this blog, I am very fond of daphnes. Infuriating as they can be because of their habit of suddenly (and I mean suddenly!) taking ill and dying. They are such beautiful plants that even this grievous fault is forgiven. Every year the old plant of D. arbuscula, given to me many ears ago by the late Duncan Lowe, gives continuing pleasure, although some years it covers itself with flowers, others not so freely. The scent is among the best of any daphne, and that as you will realise is saying a lot, and it is so compact - 30 cm across after nearly 20 years. Cuttings taken about now, when beginning to harden, are not too difficult to root, but are quite slow to make good plants.
Daphne x reichsteinii (D. alpina x petraea)
This unusual naturally-occurring hybrid from the Lake Garda region of Italy is not seen very often in gardens, which perhaps is not surprising given that, as the images show, it is a poor thing compared with either of its parents, having small flowers rather sparsely born on the newly-opened leaves, for it is deciduous like D. alpina. But I like it and the flowers certainly reward close scrutiny, both in terms of their appearance and scent. It is a slow grower, making a rounded bush 40 cm wide after 10 years.
More preposessing, perhaps, is that old favourite evergreen, D. retusa, which slowly makes a congested, rounded bush, udually smothered with flowers in late May. I have plants more than 20 years old that, with occasional judicious pruning still look vigorous and flower freely. Berries are often set so that it is easy to raise new plants. The less congested but closely related D. tangutica is equally easy but needs a good deal more space.
Daphne x hendersonii 'Kath Dryden'
In his seminal book, Daphnes, a practical guide for gardeners (Timber Press, 2006), Robin White writes, "In 1997 I pollinated a bright pink, early-flowering clone of D. petraea......with D. cneorum 'Velky Kosir'..... All had particularly bright, deep red flowers. I selected the best and named it after Kath as a small token of my appreciation for giving me my first D. petraea 'Grandiflora' in 1981". Some of you will remember Kath Dryden, one of the best growers and most formidable personalities our Society has ever produced, and for those who do it is nice to have this lovely little daphne to remember her by. My plant, which has taken 6 years to reach 20 cm in diameter, flowered properly for the first time this year, and for that reason I am including this photograph, but hopefully it will go from strength to strength producing a more even covering in future years.
There are so many plants that flower in May that it is difficult to choose a few of particular interest, but I am going to finish with a plant that I collected as seed at the Lago de la Ercina in the Picos de Europa about 30 years ago. This prostrate toadflax was growing among rocks at the lake side and it has proved to be an excellent though mildly invasive plant in my garden; but the seedlings, which are freely produced, are shallow rooting and easily removed. As I look out of my study window now patches of it are in full flower around the garden, have been for three weeks, and will be for another three. It makes a lovely short-lived perennial mat, covered in dark purple flowers, untainted by any hint of red or yellow. I have tried to run it down in various books, including Flora Europea, also online, without success, but finally found the correct name, Linaria faucicola, in Margaret and Henry Taylor's excellent new AGS book, Mountain Flower Walks: The Pyrenees and the Picos de Europa. Apparently it is endemic to the Picos.