In 1918, Martha became an admirer of the English Rock Garden and began work on an alpine garden overlooking the pond. She became one of the founders of the American Rock Garden Society. The Houghtons also worked with Charles Sargent of the Arnold Arboretum and experimented by planting many new species of primulas, inter-planting them with luxuriant native ferns for naturalized areas. The mass of delicate color, combined with spring bulbs along the paths and under dabbled shade created a paradise that one garden writer described in 1937 as "the best example in this country of becoming design-proper construction, and desirable arrangement of flower and foliage...a wonderful pageant of naturalistic beauty..."

As the garden matured, the more open feel of the woodland and rock garden changed. Shade eliminated all but a few of the birches. Dwarf conifers that were planted as miniature evergreen mounds towered over the garden. The natural progression became, in fact, the "wild garden: and has proven a great legacy of the Houghtons' lifelong passion for gardening. In the turn of the shady path and the opening of a vista, one can still experience the Houghtons' guiding hand and inspired composition.