Wakehurst's National Plant Collections
The four collections represent the most comprehensive collections of these genera in cultivation in the UK. The National Plant Collections scheme provides a further focus for their development without compromising their status as scientific collections.
What is a National Plant Collection?
National Plant Collections were instigated by Plant Heritage (formerly the NCCPG) in 1983 to conserve the rich garden flora of the British Isles. At that time, many garden plants, particularly herbaceous perennials and annuals, were being lost from cultivation. The establishment of designated collections of plants created a conservation resource by gathering together all the species and cultivars within particular genera or defined groups. These collections also serve much wider roles, particularly as comprehensive reference sources for propagation and as educational displays. Today there are over 600 National Plant Collections throughout the UK.
Betula – Birches
The longest established and most comprehensive of Wakehurst Place’s four National Plant Collections is the birch collection in Bethlehem Wood. It is regarded by several experts as being the most comprehensive in cultivation anywhere. In 1999 it was awarded scientific status by the NCCPG. Bringing together as many birch trees as possible provides the opportunity to observe the taxonomy, ornamental merit and cultivation requirements of the genus. This species is ideal for the small garden, being quick growing (but ultimately remaining a manageable size) and having several ornamental features, particularly its bark colouration. The collection already contains several named forms of Betula utilis (eg Betula utilis var. jacquemontii ‘Sauwala White’ and ‘Grayswood Ghost’) and several of hybrid origin that have Betula utilis in their parentage (eg Betula ‘Inverleith’ and Betula ‘Jermyns’).
Hypericum – St John’s worts
The Hypericum collection holds a wide range of species and cultivars, with accurate details of their origins, which have been used in taxonomic studies of the genus. It concentrates on the shrubby species in the genus and now represents over half of the shrubby hypericums in cultivation (contained in the Hypericum sections Androsaemum and Ascyreia). Most of the plants are grown in the Specimen Beds close to the Mansion, where they provide late summer colour. All the plants in the genus are yellow-flowered although they display subtle variations in colour from the primrose yellow of some introductions of Hypericum bellum to the strong glossy yellow of Hypericum ‘Hidcote’.
Hypericum is a large genus consisting of some 350 species occurring throughout the alpine, temperate and sub-tropical regions of the world. They vary from the tree-like East African Hypericum revolutum to tiny annuals. Many lesser-known species are as garden worthy as their more common relatives. Hypericum bellum has a particularly attractive dense, compact habit with finely cut, slightly downy leaves with wavy margins. Hypericum pseudohenryi has attractive pink-flushed stems and Hypericum subsessile displays rich red fruiting capsules in late summer.
The objectives for the future development of this collection are to make its coverage of the shrubby hypericums as comprehensive as possible and to increase its genetic diversity with further material of wild origin.
Nothofagus – Southern beeches
Horticulturally and botanically, Nothofagus is a most interesting genus, consisting of some 40 species found in South America, New Zealand, Tasmania, Australia, and the highlands of New Caledonia and New Guinea. As the New Caledonian or New Guinean species are unlikely to be hardy in cultivation in the UK, British horticulturists have concentrated on South American and Antipodean species. The collection at Wakehurst Place in Coates’ Wood contains 15 of the 19 species from these areas. The genetic diversity of the collection is being increased by planting specimens grown from material collected at different locations and by adding material of species not previously cultivated at Wakehurst Place. Some have been collected by Kew expeditions. This will allow a more critical assessment of the ornamental qualities of the genus.
Until now Nothofagus antarctica has often been seen in gardens as stunted misshapen specimens, no doubt originating from the southern part of its range. Further north in its distribution there are more upright and shapely trees which are more suitable for general cultivation. Another consideration is the lack of wind-firmness in the genus, clearly demonstrated by the vulnerability of Nothofagus in the great storm of October 1987. By identifying trees that are more wind-firm, their use in forestry and horticulture could be widened.
In the wild, Skimmia comprises four well-defined species, all of Asian origin. All Skimmia species currently in cultivation are represented in the collection at Wakehurst Place, and have been accurately named in line with the results of Kew’s studies of the genus.
The position with regard to the cultivars which have arisen in cultivation is much less clear. Efforts at Wakehurst are concentrated on trying to secure and grow accurately named cultivars to provide a living reference source. At present 30 of the known 53 named cultivars of Skimmia japonica subspecies japonica have been identified. These plants are located in the Winter Garden, the Chapel lawn beds, and most are concentrated in new plantings in the Kangaroo Pen. Their evergreen foliage and, in the case of female clones, berries contribute to the ornamental theme. The other species have a more limited number of cultivars. Of particular interest are the three known cultivars of Skimmia x confusa (the only genuine hybrid in the genus); all of them are grown at Wakehurst Place. A separate initiative is to introduce or reintroduce skimmias that are not presently in cultivation, eg Skimmia arborescens subspecies arborescens from the eastern Himalaya.
To obtain material for the collection, every effort is made to contact expeditions going to the areas where the plants are known to occur. Many genotypes with potential as garden plants remain to be introduced. A collection of Skimmia japonica subspecies reevesiana made in Taiwan in 1979 has proved to be a very garden-worthy plant and carries the cultivar name ‘Chilan Choice’.
National Plant Collections is a registered trademark of Plant Heritage (NCCPG).