There were three major influences which helped Dorothy and John Renton to channel their ideas and to produce a garden of international acclaim. First, there was their clear interest in the Sino-Himalayan flora: for example, the receipt of 200 packets of seed from the Ludlow and Sherriff expeditions, collected in the wilds of south-east Tibet and Bhutan. Second, their enthusiasm for complementary plant associations, perhaps influenced by the ideas of Gertrude Jekyll. The third influence which transformed much of the later development at the south end of the garden was the concept of peat-wall gardening. This was conceived at Logan House in the 1920s by building mini-terraces with turfs. The concept was taken up by the Royal Botanic Garden in Edinburgh in the 1930s but, instead of using turf, with its inherent creeping grass problem, peat blocks were used and this new method of gardening developed in parallel at Branklyn. The peat-wall areas are a historic component in both gardens and remain a feature, displaying many unusual, acid-loving plants. Alterations and new developments and, above all, new plant introductions continued through the Rentons' lifetime.

Branklyn Garden contains a spectacular rock garden and scree beds, narrow winding paths and stunning groups of rhododendrons, birches, maples and dwarf conifers giving the feel of a Himalayan hillside. The peat walls with rhododendrons, Nomocharis, Notholirion and Cassiope (of which Branklyn holds the National Collection), Meconopsis, Primula, Trillium, Phyllodoce, Kalmia, Vaccinium and Gaultheria. The garden is at its best from April through to July and again in the autumn for the spectacular autumn colour.