What is an Alpine?
Originally used to refer to montane plants from the European Alps, the term "alpine" is generally used to describe plants found growing between the tree line (the climatic limit of trees), and the zone of permanent snow or ice cover. Regions such as this occur from sea level in the Arctic to high altitudes in the tropics. The term "alpine" is also used in horticulture to describe any small or slow-growing plant suitable for growing in an alpine house or rock garden.
The planting in the Alpine House comprises permanent planting and temporary, plunged displays of specimens from the reserve collection. The plants that form the permanent display in the Alpine House are generally arranged geophytically (i.e. by the area of the world from which they come). Mediterranean (Pelargonium quercetorum, Iris mesopotanica), Southern Hemisphere (Barnaddesia arborea) and New World species (Puya pygmaea and Plectocephalus rothrockii) are all represented. The plants on temporary display are arranged by the cultural conditions they require. These are met by a variety of habitats landscaped into the house.
A large collection of bulbs is grown in the unit. This important and specialised area of horticulture supports research on petaloid monocots in the Jodrell Laboratory. A large proportion of the conservation rated accessions within the unit is bulbous, so the high rate of success in the cultivation of these species plays an essential conservation role. Within the broad group of bulbs, there are significant collections:
Dryland bulbs: These bulbs are from very arid areas experiencing only brief spells of rain. Among the species in the collection are Allium stamineum, Albuca abyssinica, and Iris postii.
Iridaceae: Members of the family Iridaceae form a large collection, including the genera Crocus, Pavonia, and Gladiolus. Of particular note in this family is the genus Iris, specifically collection of the sub-genus Scopira, Juno irises.
Araceae: The temperate members of genera in the family Araceae are grown in the Alpine Unit. This includes members of the genera Arum, Arisarum, Arisaema (Arisaema concinnum), Biarum, Typhonium (Typhonium giganteum), Pinellia (Pinellia cordata).
Tropical montane plants
Plants from high altitude locations in the tropics, such as Mt Kenya and Mt Kilamanjaro, in Kenya, form another collection. These include Espeletia hartwegiana, Hypeocharis biloba, and Altensteinia paleacea.
Southern hemisphere plants
Southern hemisphere plants from the mountainous regions of the south island of New Zealand, the Cape of South Africa, Tasmania, and the Andes form another special collection. Examples of species held in the collection are Pachysteiga insignis var. minor, Lomatia tasmanica, and Rhodohypoxis baurii.
Specimen plants are regularly submitted to be judged at the Royal Horticultural Society's shows. The following are just some of the hundreds of awards received:
Botanical Certificates have been awarded to Eremurus persicus, Salvia carduacea, and Allium grosii, among others;
the Award of Merit has been awarded to Eriogonum corcatum, Leucocoryne pauciflora, and Iris vicaria, among others;
Certificates of Cultural Commendation have been given to many accessions, including Cypripedium formosanum, Iris narbutii, and Muscari parviflorum.