Garden Features

Azalea Garden

The Azalea Garden provides good examples of hardy Azaleas that can be used in both small and large gardens. They provide a blaze of colour which, when planted with other woodland species of plants, ensures a spectacular late springtime show. They grow best in areas with moderate rainfall on acidic, well-drained but moisture-retentive soils that are rich in organic matter. At Kew, the Azalea beds are mulched with bark annually, which helps to suppress weed growth, increase the acidity of the soil, and retain moisture within the soil, resulting in healthier plant growth.

The design of the Azalea Garden sets out to illustrate the development of the deciduous Azalea hybrids.

The species used in breeding are planted in the beds in Azalea Walk leading into the Garden. More beds are arranged in two concentric circles and are planted with the 12 different groups of Azalea hybrids in order of historical appearance, beginning with the Ghent hybrids of the 1820s and following through to the modern eastern American hybrids.

The hybrid groups represented in the garden are as follows:

Ghent Hybrids: arose from a series of crosses between Azaleas from eastern North America. Carried out by P. Mortier in the 1820s, a baker in Ghent, Belgium who possibly used the heat from his ovens to bring on late-flowering species so that the could be crossed with the earlier flowering species.

Mollis Hybrids: mainly derived from Rhododendron japonicum and other Asian species. First selections were made by Lois van Houtte of Belgium working with plants grown from seed collected in Japan in 1861.

Occidentale Hybrids: occur from the species Rhododendron occidentale found on the Pacific coast of North America. This species was discovered in 1827 and seed was sent to Veitch nursery in Britain in the 1850s.

Knap Hill Hybrids: originated at the Knap Hill nursery of Anthony Waterer & Son and were the result of a breeding programme to improve the Ghent Hybrids.

Exbury Hybrids: In 1922, Lionel de Rothschild of Exbury, obtained several Knap Hill seedlings from which he bred a further series of hybrids during the next 15 years.

Girard Hybrids: bred by Peter Girard of the USA for their disease resistance and hardiness and as such are still popular today.

Ilam Hybrids: Edgar Stead of Ilam, New Zealand originally recombined Knap Hill hybrids with species from the Luteum subseries, though today Ilam hybrids now include all deciduous Azaleas from New Zealand.

Slonecker Hybrids: Howard Slonecker developed Azalea hybrids which were adapted to conditions prevailing on the west coast of North America. These hybrids are some of the hardiest around and plants can survive temperatures of up to -23°C.

Windsor Hybrids: In 1932 Sir Eric Savill obtained seedlings of Exbury Hybrids. Over the next 25 years these were crossed, producing 10,000 plants per year, and the best were selected for clearness of colour, size of flower and commercial value.

Rustica Flore Pleno Hybrids: These double-flowered hybrids were introduced about 1890 by Charles Vuylsteke of Belgium. Their origin is unknown, although they may have resulted from a cross between double Ghent azaleas and Mollis hybrids.

Eastern American Hybrids: Since the 1950s North American gardeners and breeders have been selecting clones of native species and using them in breeding programmes which aims to extend the flowering period, increase cold hardiness and heat tolerance.

Feliz and Dijkhuis Viscosum Hybrids: Feliz and Dijkhuis of Boskoop in the Netherlands first registered the Viscosum hybrids in the 1960s, and these are gaining popularity in Europe and North America.

Tender Azaleas can be seen in the Temperate House.

The Azalea Garden is number 3 on the Visitor Map.