Known as the Hidden Valley, the land dates from the 1870s but was full of gorse and broom until cleared in the 1960s. Grass was then sown and the springs drained. Extensive plantings of rhododendrons, conifers and silver birches were established at that time and a deer park was also created. Twenty years later the creek beds were developed with bog plants, and since then herbaceous perennials have been extensively planted. Today, streams meander throughout the valley bordered by sealed path-ways.
Early spring is announced by the daffodils, meconopsis, camellias, cherry blossom and magnolias.
The rhododendron collection includes large beds of R. yunnanense, R. decorum and R. spinuliferum all grown from seed gathered in the wilds of the Yunnan Province in China. In November the streams and ponds are lush with gunneras, hostas, irises and candelabra primulas. Peonies, daylilies and ajuga groundcover add to the colour as summer progresses. The deciduous foliage provides brilliant autumn colour from the weeping maples to the oaks, twisty willows and silver birches shading the picnic tables. Then winter brings the hellebores into flower.