As the Denver Botanic’s Water-Smart Garden turns 10, its designer celebrates its hardworking plants
by LAUREN SPRINGER OGDEN
Denver is a city of horticultural contrasts. From the start it has portrayed itself as a green oasis in the harsh Interior West, yet this same oasis is the birthplace of the water-conserving xeriscape movement. Lawn- and golf course-dominated developments stand off against water-thrifty landscapes and gardens. Only the climate will have the final word on how it all plays out.
Apart from this rancor, the Water-Smart Garden at the Denver Botanic Gardens has been showing people that a low-water garden can indeed be an oasis as well. Back in 1995, when I was asked to design it, 1 knew I had to make a strong case for water-thrifty plantings. This relatively small garden boasts a remarkably rich and varied palette of drought-tolerant plants. Unlike the more common segregation of native plants into their own gardens, here a multitude of the showiest natives intermingle with exotics in an informal textural style that has unique regional resonance. The Water-Smart Garden receives on average seven to ten waterings during the growing season, less than one-fifth the water a typical lawn-dominated landscape in Colorado gets.
CHALLENGE AND CHANCE
At first, the chosen site made me cringe. It was small enough to offer a sense of intimacy, something often lacking in public garden designs, but its setting was daunting. The narrow, sloping planting strip runs 180 feet along the south side of a huge glass and concrete conservatory. It is surrounded by more cement on all sides, thanks to overbuilt walls and paving and gargantuan light posts. These architectural features roar heat back onto the strip—where the soil turned out to be sandy, alkaline, and nutrient-poor, probably backfill brought in when the conservatory was built. Our local mineral-rich, water-retentive clay would have been much more desirable.
Surprisingly, the site turned out to be ideal. Prominent and visible, it runs along a main pathway close to the entrance of the gardens, so few visitors leave without seeing what a regionally evocative, water-conscious garden looks like. The scruffy existing planting included some lovely native western plants. I incorporated the best woody specimens and succulents, most notably a backdrop of mature pinyon pines and a large bank of Yucca baccata, into my design. I added a secondary path of crushed gravel down the center of the strip, and curator Dan Johnson later created a smaller planting on the other side of the wide concrete path that separates the garden from the sunken grass amphitheater below. These two elements have given the garden more immediacy and intimacy. The heat and drought of the site make for honest testing of “water-smartness.” Because the site stays slightly warmer in winter, marginally hardy species can also be tried.
My challenge as designer was not, as one might expect, to find a variety of attractive plants that would thrive on the difficult site—my plate overflowed with possibilities—but to make a cohesive garden, one that is bold enough to stand up to the hard architectural features that engulf it, yet that retains the personal feel of a private garden and provides year-round interest in its prominent spot. I focused on contrasting and harmonizing foliages, with emphasis on texture and form. My eye is naturally prejudiced this way; while I love color, it is rarely the overriding theme. Many drought-tolerant western North American natives, Mediterranean subshrubs, herbs, and rock garden plants have arresting, often evergreen foliage and comely shapes, compared to the floppy deciduous foliage and amorphous silhouettes commonly seen in well-watered perennial gardens. The Water-Smart Garden presented a perfect situation for my textural approach.
Plants with powerful forms became visual anchors: the strong, explosive foliage of yuccas, agaves, nolinas, and dasylirions; self-sowing stately mulleins of various species; the large-padded prickly pear Opuntia phaeacantha; tall bearded iris; the wiry blue joint fir (Ephedra equisetina); and sea kale (Crambe maritima), whose lolling turquoise leaves make it a personal favorite. Grasses threaded throughout add lightness and motion: short-lived blue fescue (Festuca glauca) and Mexican feather grass (Nassella tenuissima) have reseeded and are still major players in the planting today. The original blue fountains of Helictotrichon sempervirens persist admirably, and new grass species have been added, too.
Silver and blue foliages repeat throughout the planting, giving it unity. Fine-textured small shrubs Artemisia, Seriphidium, Santolina, and Lavandula spp., Russian sage (Perovskia xhybrida), rabbit brush (Ericameria spp.), Apache plume (Fallugiaparadoxa), and lead plant (Amorpha canescens, A. nana) set off the large foliage rosettes of furry Salvia argentea, its aromatic cousin clary (S. sclarea), and self-sowing ruffled blue horned poppies (Glaucium spp.). Flowers come and go, beginning midwinter with small bulbs and peaking in spring and early summer, taking a rest during the hottest weather and reprising in early autumn. In the bright sunlight, with a backdrop of gray cement and silver and blue foliages, all flower colors mingle and blend happily, never jarring as they would in softer light or with green as a foliar foil.
The garden’s evolution from initial design to the mature, popular destination it is today is marked by the influences of three people. At the very outset, I had one of the worlds finest and most generous plantsmen close at hand. Panayoti Kelaidis was the inspiration and practical source for many of the plants 1 chose to include. I had grown most of them in my own garden for several years after annual raids on Panayotis seed stash. Favorites became major players in the Water-Smart Garden. Thanks to Panayoti’s plant pioneering and generosity, one of the gardens great successes has been bringing obscure but superb plants to the public eye, and then into nursery production and out to people’s gardens.
The Denver Botanic Gardens’ former director of horticulture, Rob Proctor, played a crucial role in developing the full potential of the garden. The first couple of years it floundered—a good number of the called-for plants were not actually put in, and it fell under poorly trained and often careless maintenance. When Rob look over, he made it his priority to support the richness of the planting and the high level of care the garden deserved. He let me shop personally for many of the missing plants and add the beginnings of a collection of fiber plants that now brings so much to the dynamic year-round textures of the garden: nolinas, yuccas, agaves, and dasylirions—plants that just a few years ago were rarely used in Colorado gardens and often thought not to be hardy. Rob also put an exceptionally talented plantsman and designer, Dan Johnson, in charge of the garden.
It is a rare day when a professional gardener comes along with the passion, integrity, knowledge, and artistic eye to turn a public planting into something with the personality, complexity, and careful stewardship typical of a private space. Dan Johnson has done that in all the areas of the Denver Botanic Gardens on which he has worked, and the Water-Smart Garden would not be what it is without him. A garden that relies as heavily on texture and form as this one does requires a most sophisticated sense of care. Primping is a constant decision of how the textures interplay, not simply one of removing spent flowers or pulling weeds. Dan’s plantsmanship and artistic eye become even more important as the garden evolves. Many of the older plants are maturing beyond their peak and need renewal pruning or judicious removal. Many new plants have gone in, and many more will continue to be added to the fray. Dan has been experimenting with a whole new palette of Mediterranean and southwestern natives, pushing the envelope on hardiness, and meeting challenges—all while still maintaining a sense of design and overall textiiral cohesion.
My wish is that he continue to steward the garden as the cohesive composition it is when at its best, keeping it from becoming a mere collection or trial area. Then the Water-Smart Gardens special plants and unique style can continue to be a source of inspiration for making beautiful, regionally evocative, environmentally intelligent gardens. H