The garden and arboretum in all cover about 15 acres. The garden, purchased in 1971, comprises some 5 acres of mainly woody plants, underplanted with bulbs and herbaceous ground cover. It is situated on a broad ridge of about 500ft elevation east of Sevenoaks, and at its centre is the site of a shallow ragstone quarry with gently undulating areas of disturbed soil. The remaining native soil is a light acid loam with occasional narrow clay seams. The first plantings were made in the late 1970s and early 1980s by Rosemary and Maurice Foster while both were still working in London. With the exception of a century-old bramley apple tree beside the house, every single tree and shrub in the now 50 year-old garden at White House Farm was planted by them in ground cleared by hand.
Development accelerated after 1992 when Maurice retired to devote himself to the garden full time, inspired in part by his first plant hunting trips to Bhutan and Western China. His aim has been to integrate flower, fruit, foliage and form in pleasing combination, to create colour and interest throughout the year, and as a solo woody gardener, to minimize maintenance and reduce labour. Plants are propagated on site, by seeds, cuttings and grafting.
Magnolias, rhododendrons and camellias are a major feature of spring along with collections of cyclamen, snowdrops and daffodils. Many roses, particularly tree-climbers, provide midsummer profusion and a large collection of hydrangeas late summer colour. These are complemented by wisteria, clematis, philadelphus, deutzia, cotoneaster, hypericum, indigofera, mahonia, viburnum and many other woody plants. Autumn colour is also a feature of the plantings.Maurice Foster
In 1994 Maurice seized the opportunity to purchase an adjacent pick-your-own strawberry field and bramley orchard to develop into a 7-acre arboretum for wild-collected plants of known provenance, the result of many institutional and private expeditions to which he subscribed or in which he participated in the 1990s and early 2000s. He took trips to China, Pakistan, Mongolia, Japan, Tasmania, and New Zealand: 13 expeditions in all. China, with its estimated 30,000 species of higher plants, was the real treasure-house, with discoveries in Yunnan, Sichuan, Guangxi, and Hunan, including some plants described by or preserved as herbarium specimens by the previous century’s planthunters, either lost since then or not yet introduced to cultivation, such as Rhododendron davidii and Betula skvortsovii.
In 2009 a 3-acre wood was added, now integrated into the arboretum. It is home to trees and shrubs of wild provenance and to many of WHF’s own hybrids that enjoy shelter and shade, including two hydrangea walks (serrata and aspera), as well as camellia and rhododendron species and woodland floor species such as bluebell, snowdrop, daffodil, lilium, epimedium and anemone.
Today the arboretum and wood feature plants from most cool temperate regions of the world, including China, Japan, Korea, the Himalaya, Mongolia, Mexico, Pakistan and the Americas. Most cool temperate tree genera are represented, including acer, alnus, betula, carpinus, malus, prunus, quercus, sorbus and tilia. More recent additions include flowering trees such as selections of staphylea, corylopsis, meliodendron and rhederodendron. These trees are supported by collections of rose species, cotoneaster, berberis, deutzia, philadelphus et alia. A notable feature are the many vigorous climbing roses species and wisterias in the boundary and shelter trees, with climbing hydrangeas in the wood.
The collections at WHF were considered of sufficient scientific, educational and conservation value that in 2019 a charity was created to preserve the arboretum and wood for posterity. Maurice gifted the land to create the White House Farm Arboretum Foundation (WHFAF) which is supported by endowment funds sufficient to maintain the collection.