Gardeners tend to associate colors with a season: the delicate pastels of spring ephemerals, the hot reds and yellows of high summer, and the dusky jewel tones of autumn.
In the gardener's palette, white is often a bit player, serving to separate contrasting shades or as a backdrop to more eye-catching hues. The noonday sun does white blossoms no favors, often making them appear flat and washed out. But in the evening, white flowers can be transformed into star players with magical appeal. As daylight fades, white flowers emerge from their backdrop of green foliage, reflecting the soft light of the early evening.
Vita Sackville West's famed White Garden at Sissinghurst Castle in Kent, England, is a legendary example of an all white garden. Needless to say, most of us lack the money, real estate and hired help to create anything on that scale. However, a white garden can be as simple as a pot of white petunias on an apartment balcony, moonflower trailing near a patio, or a patch of white flowers or gray foliage glimmering in the perennial border or annual bed. Especially for those who work during the day, adding white accents is a clever way to maximize the garden's appeal when we are actually home to enjoy it.
A moon garden takes the white garden concept one step further. It consists of white flowers illuminated by an artificial light source. The white blossoms reflect the artificial light much as the moon reflects the light of the sun. Nothing too extravagant is needed here. In urban and suburban gardens, a nearby window or streetlight or a simple string of fairy lights is often sufficient to make white flowers step out of the shadows. Nor does the lighting source require electricity; candles, lanterns and torches can provide the same effect.
The key feature of a moon garden is white flowers and plenty of them. The best choices are plants that feature large flowers or a profusion of small flowers. They need not be exotic or expensive plants.
As with any gardening project, a good first step is to begin with what you love. Be it lily or lilac, crocus or cosmos, there is very likely a white variant that you will find appealing. Low-maintenance annuals such as petunias and sweet alyssum can be invaluable players in the moon garden. They will demand some extra care in terms of watering but will repay you with soft luminescence at the feet of taller plants. Normally a white impatiens would fill this role as well, but impatiens are best avoided at the moment due to the prevalence of downy mildew.
In addition to white flowers, common features of a white garden often include fragrant flowers, night bloomers and plants with variegated foliage.
What better plant to feature in a moon garden than moonflower (Ipomea alba)? It is a vigorous vine that features large, pure white flowers that bloom only at night and release a sweet fragrance. Moonflower blooms rather late in the season and can add charm and fragrance to a late summer garden. Angel's trumpet (Brugmansia spp) is another night bloomer whose large, downward-hanging, trumpet-shaped flowers will add drama to any garden.
Night blooming flowers are often intensely fragrant in order to attract night-time pollinators such as moths and even bats. There is some evidence that evening pollinators are drawn to the color white itself. In addition to moonflower and angel's trumpet, fragrant flowers for a white garden include peonies, mock orange, white lavender, white lilac, summersweet clethra and honeysuckle. Content in partial shade during the day, fragrant woodland tobacco (Nicotiana sylvestris) will add height and drama to a white garden. With tubular white flowers atop bold floppy leaves, N. sylvestris can reach 6 feet in height. For a smaller garden, its shorter cousin, Nicotiana alata, is a good choice.
Variegated foliage can also contribute to the allure of a white garden. The silver tones of lamb's ear, artemisia, or a silver accented sage or thyme will enhance the visual impact of nearby white flowers. Blue-tinted foliage, as in some hostas and rues, can offer a counterpoint to the palette of green and white. In addition to their silvery or variegated foliage, these plants also feature interesting leaf shapes or plant forms, which are useful for creating and sustaining interest in a monochromatic color scheme.
When choosing from the spectrum of color available to plant in your garden, be sure to consider the power of white. It will add a glow to your landscape and allow you to enjoy the visual effects of your planting long after the sun goes down.
Kate DeSimone is a Penn State master gardener. Columns by master gardeners sometimes appear in place of the Garden Q&A by Sandy Feather, a Penn State Extension educator.