You need commitment to grow alpine plants, but it's worthwhile, writes Jane Powers
The alpine bed in our garden was harrowing to build, involving an injured ego and thumb and a temper ignobly lost among the skittish granite rocks. The temper, I'm sorry to say, was mine; the other bits belonged to my virtuous co-builder. Yet, half a dozen years later, this tiny raised bed, not much more than a metre square (what was all the fuss about?) is a favourite part of the garden, its dainty treasures offered up within easy gazing range. Even its other creator, who is unmoved by much of what goes on among the plants unless he can eat them, is likely to inquire with a soft warmth in his voice: "What are those little pinky yokes in the alpine bed?"
The pinky yokes, at this time of the season, might be diminutive tulips, the species kinds that come up year after year, such as 'Eastern Star' and 'Little Beauty'. Or perhaps they're Cyclamen repandum, with its whooshed-back petals and, according to the books, a light perfume (which I am unable to detect).
A few weeks later there are more pinky yokes: sheets of Rhodohypoxis baurii, the South African six-pointed star, and its fellow national Babiana stricta, or baboon root, which looks like a miniature gladiolus - indeed, it is from the same family, Iridaceae. Its common name refers to the fact that, in South Africa, baboons are supposed to collect the corms - the swollen stem bases, which the plants use as storage space - for food.
And some of our pinky things are pinks: smaller members of the Dianthus genus. They are so named not because of their rosy hue but because the petals look as if they have been cut with a pinking shears.
Experienced gardeners will notice that all the above are not strictly alpines - plants whose native habitat is above the treeline on inhospitable mountainsides. Most true alpines have tiny, closely-packed leaves and a dwarf, compact habit, allowing them to nestle under the snow for months and to be impervious to the winds that buffet them after the melt. The growing season is short, leaving little time to attract pollinating insects. Consequently, when they bloom they pull out all the stops, blasting out an intense and colourful fanfare of flowers, which advertises their presence up and down the slopes.
I don't grow true alpines because I can't replicate their conditions in my garden, especially the long months when they're snuggled under an insulating blanket of snow, protected from excess cold and wet. Irish winters, with their stodgy, rainy and root-rotting weather, are too much of a challenge for me.
Not so, however, for the dedicated alpinists who go to great trouble, often in carefully ventilated houses, to cosset treasures such as the so-called cushion plants or "buns". In spring their perfect grey mounds of muscular, tight foliage erupt into a rash of equally perfect flowers. Dionysia, a member of the primula family, is one such domed curiosity; it looks like a toy hillock starred with doll's primroses.
But back to the easily grown "alpines", more properly called rock-garden plants - a title that embraces all plants that are small, visually appealing and look best growing in a specially constructed bed, in a rockscape or in a container such as a trough. Such little gems are perfect for today's tiny gardens, as well as for the windswept balconies and window boxes that are the only outdoor spaces many city apartments enjoy.
If you grow them in troughs, or other generously sized planters, you can create a completely different habitat in each container by varying the compost and where you place it in the garden. A trough with a gritty mixture in a bright spot would be ideal for sun-lovers such as dianthus and sempervivum, while a container with a more humus-rich compost in a shady area would be suitable for dwarf species of the woodlanders trillium and corydalis.
Alpines and rock plants do well in raised beds, where the extra drainage ensures that their roots are never waterlogged (and a top dressing of fine gravel or coarse grit stops moisture from collecting around their vulnerable necks). The height in a raised bed makes weeding easier and brings prized specimens closer to the eye.
Finally, a word on rockeries. Don't. That is, don't dream of constructing one unless you can provide proper drainage, an utterly weed-free growing medium and a result that doesn't look as if someone has tipped a load of rubble out of a wheelbarrow. A decent rockery or alpine garden must be carefully built on a layered substratum of soil, grit and stone, and the rocks expertly placed.
And, just in case you have a spare heap of soil (the spoil from a water feature, for example) and plan on garnishing it with rocks, be assured that it will be dreadful to behold, and make a perfect home for weeds. The gorgeous yokes that the great Irish gardener and writer William Robinson called the "loveliest children" of the "mother of earth-life" deserve only the best.
EASY ROCK-GARDEN PLANTS
Most garden centres have inexpensive plants in little pots labelled "alpine". Experiment with these or choose from the list below. (Many of the species mentioned have more than one variety.) We don't have space to describe them here, but you can search for them on the internet or find them in a book. And remember that many bulbous plants, such as dwarf iris, narcissus and tulip, are ideal for the alpine bed or container.
Aethionema, alyssum, Anemone blanda, arabis; Armeria maritima and A. juniperifolia; Aubreita; small campanulas such as C. betulifolia, C. cochleariifolia and C. pulla, Corydalis solida, cyclamen, small dianthus such as D. alpina and D. deltoides, Dodecatheon meadia, gentian, miniature geraniums such as G. sanguineum and 'Ballerina', helianthemum, Ipheoin, Lewisia, Phlox douglasii and P. subulata, primula, pulsatilla Rhodohypoxis baurii, saxifrage; small sedum; sempervivum, thyme, Zauchneria californica subsp. cana 'Dublin'.
WHERE TO SEE THEM
The Alpine House at the National Botanic Gardens, Glasnevin, Dublin 9. Open daily, 9am-6pm.
The Alpine Garden Society (Dublin Group) holds its spring show and plant sale, 1.30-4pm, next Saturday at Cabinteely Community School, Johnstown Road, Cabinteely, Co Dublin.
ON THE WEB
www.nargs.org. The site of the North American Rock Garden Society includes a potted history of rock gardens and an interesting plant-of-the-month archive.
www.thealpinegarden.com includes tips on making a rock or trough garden, hundreds of photographs of alpine plants and links to other useful alpine websites.