by SCOTT OGDEN and LAUREN SPRINGER OGDEN
Choose plants that play with strong light to bring new vision to a sunny garden
UNLIKE MORE STATIC PIECES OF ART, gardens reflect forces beyond the control of their makers. Gardens look different over the years, over the seasons, even over the course of one day. This is not just because plants have wills of their own. Much of this change is due to light.
Many gardeners use color as the starting point for design decisions, paying little or no attention to the ways in which colors change in response to light. But the strength and quality of the light demand critical consideration in planning a garden. Our own two gardens, in Colorado and in Texas, for example, are bathed in some of the strongest light in the northern hemisphere. Under this potent, relentless sun we’ve learned to rely as much or more on plants‘ forms and textures as on color to create dependable, lasting beauty. Although all of Norm America isn’t this extreme, most of the continent basks in such brightness at some times of the year. Fortunately when plants’ textures and forms are well chosen and placed to respond to strong light, a garden becomes as complex and satisfying as, and arguably more dynamic than, one based solely on intricate color harmonies and contrasts.
UNDERSTAND THE EFFECTS
Designing in response to light begins with understanding the different luminous effects of plants. The polished needles of many pines, the waxy leaves of hollies and boxwood, and the silken petals of ice plants all shine in strong sun. Other plants are so silvery they appear almost white. In the searing sun of southwest Texas, the felted gray leaves of purple sage (Leucophyllum spp.) shimmer amid the brush; in Colorado’s crystalline light, silver sage (Artemisia ludoviciana) gleams among the montane grass. Both shining and silver plants exemplify reflectivity–plant surfaces bouncing light into the landscape, as glittering highlights or diffuse brightness. Other leaves and flowers, such as the delicate blossoms of spring bulbs, the watery summer leaves of cannas, and the diaphanous fall foliage of maples, glow in sunlight. This is translucence–light passing through the plants and radiating into the garden.
Reflectivity and translucence are not static factors; they vary with light and also with the growth cycle of plants. You can appreciate this change by walking in a deciduous forest at different times of the year. The luminous fresh green light of the spring canopy passes to a more somber summer green produced by the mature matte or reflective foliage. Those same leaves transmit light once again as they age in the brilliant sunlight of fall
Facing page: Fine-textured bottlebrush grass (Elymus hystrix)blazes in a world of light. This page, right: Young variegated hosta foliage catches the spring sun. Far right: Sunlight creates a deceptively soft bronze halo around fuzzy-spined pads of Opuntia acicularis; Agave weberi provides a shadowy backdrop.
Strong Light, Special Effects
Star Quality: A few of the Ogdens favorite plants that really play with strong light
Amsonia hubrichtii(willow-leaf bluestar)-foliage
Cotinus spp. (smokebush)-flowers
Echium spp.-hairy stems and leaves
Foeniculum vulgare (fennel)–foliage
Pulsatilla spp. (pasqueflower)-flowers and seedheads
Salix spp. (willow)-some species’ flowers
Stachys byzantma (lamb’s ear)-hairy stems and leaves
ARCHITECTURAL PLANTS SCULPTED BY LIGHT:
Dasylirion spp. (stool)-foliage
grasses and sedges-foliage and flowers
Iris pallida Aureovariegata’. ‘Argemeovariegata’ (striped bearded iris)–foliage
Nolina spp. (bear grass)-foliage and flowers
Shining Plants: These plants are reflective-light bounces off their surfaces, creating a distinct highlight or diffuse brightness.
Bergenia spp. -foliage
Buxus spp. (boxwood)-foliage
Camellia sasanqua -foliage
IIex spp. (hollyHoliage. and some species’ fruit
Magnolia grandiflora (southern magnolia)-foliage pines-foliage
Prunus caroliniana (cherry laurel)-foliage
Sciadopitys verticillata (umbrella pine)-foliage
Temstroemia gymnanthera (Japanese cleyera)-foliage
Viburnum awabuki ‘Chindo’-foliage
Glowing Plants: These plants exhibit translucence-light passes through them, creating a radiant glow.
Alocasia and Colocasia spp. (elephant ears)-foliage
Canna spp.-foliage and flowers
Cercidiphyllum japonicum (katsura tree)-foliage
Chionanthus virginicus (fringe tree]-flowers and foliage
Imperata cylindrica var. koenigii ‘Red Baron’ (Japanese blood grass)-foliage
Kniphofia spp. (red hot poker)-flowers
maples-foliage and samaras
Musa spp. (banana)-foliage
One of she most interesting design effects mixes plants thai glitter with those that glow–in other words, combining reflectivity with translusence. Backlit streaks of Japanese blood grass (Imperata cytindrica var. koenigii ‘Red Baron’) smolder red next to glittering emerald rosettes of bergenia. Although gleaming plants such as the bergenia can be placed anywhere, glowing subjects such as the grass demand thoughtful placement to catch the low morning or evening light. Harnessing natural sunlight for backlighting effects requires siting translucent plants along a general east-west axis so that the plants are viewed with the sun behind them. Our steppe, which is on the west side of our property, is interplanted with small early bulbs that glow jewel-like in the setting sun.
Plants whose silver leaves reflect light diffusely look their brightest when light shines directly on them rather than from behind. Dusty miller (Senecio cineraria), for example, is so pale that it shines even on the dullest days, but given a straight shot of sunshine, it radiates white light. When backlit, however, silver plants such as this blur to muddy gray.
Fine textures such as feathery foliage, surface hairs, spines, and gossamer seed heads trap light. Common lamb’s ear (Stachys byzantina), for example, is enveloped in a furry halo when the sun shines behind it. Our steppe, which we created to replace an uneventful lawn, takes on a shimmering summer countenance when the fluffy seed heads of prairie smoke (Geum triflorum)and pasqueflowers (Pufeotilla spp.) and the soft plumes of low grasses begin to fluoresce as the sun’s rays play across them.
Light emphasizes not only fine textures but also variegations and bold forms, Interspersed in a garden, these produce a diverse scene, satisfying unto itself but also a tine backdrop to the ephemeral colors of seasonal bloom. Luminous throughout the growing season in backlit situations, the swordlike leaves of striped bearded iris (Iris pallida ‘Aureovariegata’; syn. ‘Variegata’) are joined in early summer by gleaming poppies.
By their very nature, strongly architectural plants create plays of light and shadow. Palms, agaves, yuccas, sotols, cacti, and other boldly structural plants not only grow well in strong sun but also look their best. Some, such as sotols and cacti, have spines along the edges of their foliage or stems that trap or transmit light, enhancing the plants’ – forms, filaments or translucent margins on leaves ignite similarly dramatic effects. Sculpted by ever-changing sunlight, these textural plants fill the void when flowers ebb. In our Texas garden, while blossoms wane in the brutal heat of midsummer, rays of sun catch the fishbone silhouettes of cycad leaves, soft radiance of frothy asparagus, and fresh exuberant foliage of bananas and elephant ears.
As light changes over the seasons, so do the plants that respond to its mercurial qualities. Autumn in Colorado is gilded by a more mellow, warmly hued sun that makes the lavenders and purples of asters and fall crocus glow, deepens the golds of the ubiquitous composites, and animates the tawny grasses in our garden and on the hills beyond.
In Texas, low-angled winter light washes across the somber green live oaks and our shiny sedge lawn, and moves on to catch the parchmentlike petals of tazetta narcissi and burning orange torches of Knipliofia ‘Christmas Cheer’ blooming throughout the garden.
As spring returns to Colorado and the sun intensifies, crocus, snow iris, and species tulips are teased from the ground, their rich hues illuminated as they open their chalices to the warmth. Silvery pussy willow buds and red-infused unfurling peony foliage along with lacy bronze fennel shoots harness the strong yet pale light of March and April.
Whether over the seasons or over the course of one day, changes in light and their effects on plants create moments of incandescent beauty that may be anticipated but still remain partly beyond the gardener’s intent. Such surrender of control frees us to connect with nature and the rhythms of Our surroundings in ways seldom appreciated in more contrived garden spaces. H