Attempting to grow alpines at an elevation close to sea level may seem an absurd endeavour. However, no one interested in gardening needs to be reminded that good alpine plants flourish almost within the range of sea-spray in the Burren. The cliffs in Howth support at least one true arctic-alpine plant, Armeria maritima (Thrift).

Rock gardens are, of course, planted with many exotic plants as well as natives. The exotics include species from all the continents (excluding Antarctica), and from diverse habitats, many of which are not alpine in the strict sense of being above the tree line. Some of the exotic plants thrive in our conditions with the minimum of care, some require special treatment and some are well-nigh impossible to grow. Strangely many exotics can be grown quite easily, while some of our native plants, for example, Polygala calcarea (Milkwort), are very difficult to maintain in cultivation.

Sometimes the lack of success in cultivating a particular plant is a result of not appreciating the conditions that it requires to flourish. A case in point is the exceptionally beautiful relative of African violets and ramondas, Jankaea heldreichii, which is found on Mount Olympus in Greece. Conventional wisdom dictated that jankaea had to be grown in an alpine house so that it could be kept dry and to prevent water lodging in the rosette of hairy leaves, causing them to rot and the plant to die. To raise a plant to flowering size was considered a rare achievement and to keep it alive thereafter, rarer still. On Mount Olympus, jankaea grows in cliff ledges, shaded from the full glare of the sun, and is commonly enveloped in mist and soaked by rain showers, suggesting that conventional wisdom in this case was somewhat misguided. A Dutch grower of alpines, Harry Jans, tried a completely novel method of growing jankaea by planting small plants in holes in a vertical wall made of tufa, a porous calcareous rock, in which many alpines thrive. The tufa is watered from pipes behind the wall so that it does not dry out and the plants are sprayed in hot weather. Because the plants grow with their rosettes parallel to the vertical wall, water does not lodge and lead to rotting of the foliage. The Jans jankaea have grown, and flowered, and even seeded into the wall. However, there are other plants, such as the jewel-like blue Eritrichium nanum (richly deserving of its name 'King of the Alps'), which is intractable in cultivation, even though it grows cheek by jowl with plants, such as Silene acaulis (Moss Campion), which are easy to grow in our lowland gardens.

Howth has had some famous rock gardens in the past. Glenlion, constructed by Professor Bayley Butler after the first World War, seems to have been a particularly eccentric undertaking. If you have ever wondered about the origin of the Kniphofias (Red hot pokers) and other decidedly exotic species on the cliffs around Glenlion, wonder no more. A thousand Colchicum (Autumn crocus) bulbs were also planted but they did not survive. Mrs Guinness' garden, Danesfort, was home to some exceptional plants, a few of which have been propagated and are still grown in Dublin gardens. One which you may occasionally find offered for sale is a very good form of Grevillea alpina. If you grow it, you are maintaining the legacy of Howth alpines. Very few of the readers of this article will aspire to gardens the size of Glenlion and Danesfort, but wherever you live in Howth and in whatever size and aspect of garden, there are alpine plants which will grow for you and will form the basis of an absorbing hobby.

The opinions expressed in this publication are those of the authors and need not necessarily represent the views of the Society.