There are similarities between painting a room and painting a garden: the powers of some colors to excite and of others to soothe, and the risk of making a real hash of it.
The chief difference is that a room can be repainted fairly easily.
It is much harder to fix a whole chorus of plants that have sprouted off-key.
Another truth: Painting is one of the quickest and cheapest ways to transform a room. Coloring with plants arguably is the most challenging aspect of gardening, because it can take years to amass the knowledge needed to pull it off. That is not meant to be discouraging. Gardeners who are quicker studies than I who have become great colorists in relatively short order.
This principle, though, is worth mulling: Color is not the least of a garden’s building blocks, but it should be the last. Other aspects must be addressed first, such as forming spaces with structures and architectural plants, framing views, and choosing plants for their contrasting forms and textures.
The color wheel drives considerations as much outdoors as inside, and it’s probably no accident that some of the most accomplished gardeners started off as painters, notably Gertrude Jekyll, the matriarch of the modern garden.
Colors next to each other on the wheel make for pleasing combinations.
Violet with mauve, for example, or blue with blue-green.
Colors that are opposite form complementary relationships that make each hue seem brighter. Jekyll in her book “Colour in the Flower Garden” says that if you stare for 30 seconds at the bright-orange flower of the African marigold and then look at the green leaves, the foliage seems blue.
Whites tend to mute the more riotous colors and tie hues together, but plants with gray or blue- green foliage also are effective at linking colors that need a bridge. For that reason, silver-leafed lavender, artemisias, perovskia, santolinas and lamb’s ears are highly effective at bridging perennials, as are rue, catmint, blueish hostas and pinks.
Jekyll tended to create sequences of solid colors; her own famous flower border was like a rainbow, with hot reds and oranges sandwiched by cooler compositions.
Two hundred feet long, it began at one end with perennials full of soothing gray and blue- green foliage, with blossoms beginning pure blue, gray blue, white, pale yellow and pale pink, “each color in distinct masses and partly inter-grouped.”
In the center, she planted stronger yellows to set up a sizzling color scheme of oranges and reds before beginning to cool off. The flower colors recede from orange to deep yellow to pale yellow and pale pink, bridged with blue-gray foliage, before ending in purples and lilacs in contrast with the blues at the other end.
Although violet and blue are harmonious, Jekyll preferred to separate them.
Jekyll’s theories, formulated in England more than a century ago, still hold true, though modern sensibilities — not to mention lot sizes — have made the glorious experiment much less rigid and much more intimate.
Oh, and it is fine to borrow ideas from living horticulturists: One of the purposes of a botanical garden, like the Denver Botanic Gardens, is to give people direction for their own gardens.
Among the gardens I find most inspirational are two in the Bronx: the New York Botanical Garden and Wave Hill.
At the NYBG, two of the four sub-gardens of the Jane Watson Irwin Perennial Garden are experiments in color gardens, one in cool hues, the other hot. In spring it is easier to achieve combinations of cool colors — of pinks, violets, pale yellows and blues — while summer, fittingly, is the season for the more fiery hues. That is highly apparent in the Irwin garden when high summer sees the hot garden alive with crocosmias, dahlias, cannas and other loud tropicals.
I love the complementary hues of orange and blue — shocking to some — and think of late summer and early fall as an opportunity to bring them together with California poppies, orange cosmos, orange landscape roses and the saturated blue of asters, caryopteris and salvias.
“We use loads of salvias,” said Jody Payne, a curator at the New York Botanical Garden, listing Salvia sylvestris Blauhuegel and Ostfriesland as well as Salvia nemorosa. She also had a few tender plants to add to my list of late-season orange beauties: arctotis, Zinnia haageana Orange Star and the Mexican sunflower, Tithonia rotundifolia.
Proving that Gertrude Jekyll didn’t have the last word, the gardeners at Wave Hill have put together flower borders where the hues are close but not always harmonious. It is called “near dissonance,” said Scott Canning, Wave Hill’s director of horticulture.
In another bed, devoted to pink and white flowering plants, he reels off a list of delicious perennials: a creamy dahlia named Swan Lake, pink flowering heucheras, dianthus Spotty and Bath’s Pink, veronica Red Fox and two late-season Japanese anemones, Anemone Robustissima and Queen Charlotte.
