Like a certain popular pornographic novel, monochrome gardens have had their detractors. Nevertheless, as recently as summer of 2011, Julia Hess, a senior horticulturist at the celebrated Missouri Botanical Gardens in St Louis created a sensational black-and-white display in the five acres of grounds surrounding the residence of the garden’s director. Whether she was inspired by the black-and-white themed artists’ ball so ably directed by Vincent Minnelli in An American in Paris, reprised with equal success a few years later in the screen version of My Fair Lady, Hess isn’t saying. What she has admitted is that, if ever she repeated such a planting, she would add more silver plants to the palette or, more prosaically, shades of grey.
So to keep with these trendy times, one must ask why not a garden of greys? There is, after all, a positive plethora of popular perennials, hardy in temperamental climates and not difficult to discover at garden centres and nurseries worthy of the designation.
While these are valued principally for their foliage there will be, all things being equal, the inevitable flowers. Many grey- and silver-foliaged perennials feature white, yellow, pink and blue blooms, but these are not of any great concern when planning the border, for their appearance is comparatively fleeting.
All season long is the foliage. This may be featured on prostrate, short, medium or tall growth. The leaves themselves may be finely divided, almost moss-like, ribbon, medium, broad – an almost infinite variety of shape and form. While usually the lowest will be at the front of the border and the tallest occupy the rearmost regions, contrasting foliage types in close proximity to each other renders the greatest effect.
Not all suggestions listed here may be welcome, however. Snow-in-Summer, Cerastium tomentosa, can become invasive, the Cerastium indicating it to be a cousin of the notorious chickweed. And when it comes to culture, it is advisable to keep in mind that many grey foliaged perennials are evergreen . . . or should that be ‘ever-grey’? Unlike most other perennials, with the notable exception of ornamental grasses, these should not be cut back in the fall but in the following early to mid-spring.
Wes Porter is a horticultural consultant and writer based in Toronto. Wes has over 40 years of experience in both temperate and tropical horticulture from three continents.