Landscaping with Native Plants for Water Conservation
|By Lana Robinson|
All across the nation, communities faced with increased demands on existing water supplies are encouraging, and in some instances, mandating, lawn and garden strategies aimed at conserving water. Hence, over the past decade, a systematic concept for saving water through water-efficient plantings, often using native materials?has gained ground. But recently, successive, widespread droughts, along with a heightened awareness of the environmental and practical benefits of using indigenous plants, has made landscape contractors across the southern United States think native.
As an added incentive, the City of Albuquerque offers property owners up to $500 and commercial property owners up to $750 in credit on their water bills for converting turf-based landscapes to drought-tolerant plants.
?Most of what we do along the line of native landscapes is new installations, but quite often, when a business or commercial entity wants to get a building permit, it requires them to convert the landscaping to low-water use,? explained Daniell. ?Some people think of xeriscape as a bunch of gravel and a couple of weeds. We can certainly offer them a huge variety of trees, shrubs, perennials, and groundcovers.?
To create an oasis-like effect, Daniell relies on a lot of native shrubs, such as chamisa (Chrysothamnus nauseosus), Apache plume (Fallugia paradoxa), Clary sage
(Salvia sclarea), and blue mist (caryopteris), and junipers (Juniperus communis L.) for evergreens. Some popular, low water-use trees found in his xeriscapes are desert willow (Salix sp.) and the New
Mexico olive (Elaeagnus angustifolia, L.), which is native to the watersheds in northern New Mexico and Colorado.
Daniell designs turf areas in rounded, compact shapes so that they can be watered and mowed more efficiently, and watered separately from other landscape plants. Also he emphasizes the importance of choosing turf that is appropriate for the site.
?Typically, we recommend Buffalo grass (Buchloe dactyloides) and blue grama grass (Bouteloua gracilis ?Lovington?) for low water-use turf. They?re native to the area, but they?re warm season grasses. It gets a little too cold, and the altitude is too high here, for these grasses to stay green more than four or five months. We use blue grass (Poa annua L.) and fescue (festuca) for high water, but again, that?s limited to 15 percent. The rest is typically low-water use shrubs and gravel mulches,? says Daniell, adding that a study by the University of New Mexico suggests that two-inch cobblestone does the best job of holding moisture.
As far as soil preparation goes, Daniell sometimes tills a ground bark mulch into the soil for turf areas, and that?s it. ?Very often, we do not do much to improve the soil. Native plants don?t need a lot of extra stuff. It doesn?t help and, in fact, some suggest it may actually hinder native plant development,? says Daniell.
Dale Micetic, who started his irrigation contracting business in 1974, has watched it branch into three companies. Terrain Systems, Inc., Landscape Care, LLC and Southwest Tree Growers serve central Arizona.
?We use native plants that are indigenous, not necessarily to the Sonoran Desert, but to the Southwestern region,? he says. ?This past summer, we did
a job, a shopping mall in Chandler, Arizona, that was $3 million in landscape work. It was comprised of all indigenous and drought-tolerant plants?sages (salvia officinalis), salvias (i.e.
salvia greggii and salvia leucantha), cassia (Cinnamomum cassia Blume) ? many, many types of plants. They are very colorful and add life to a landscape.?
?We also use Sweet acacia (Acacia smallii) and New World acacia (Acacia Sp.), and Chilean mesquites (Prosopis chilensis). That?s a thornless variety that?s people friendly, and they provide good shade, a nice canopy for a parking lot. Live oaks (Quercus viriniana) are also growing in popularity here, as well as the Texas ebony (Pithecellobium flexicaule). It has a really deep, rich color throughout the season. Also, the Mexican Bird of Paradise (Caesalpinia mexicana) has a strong plume of red and orange color, with spectacular blooms all summer long. Ash (fraxinus americana) trees and elms (ulmus) are used extensively,? he says.
Micetic gets his supply of fruitless olives (Olea europaea ?wilsonii?), a nice multi-trunked accent tree, from his own tree farm.
?Our intent is to grow everything we use ? vertical integrations ? where you try to develop your own resources. We do that, and then turn it over to the landscape company to maintain,? he says, adding: ?We maintain 60 percent of the clients we grow for.?
Micetic?s Southwest Tree Growers operation also grows palms. He says date palms (Phoenix dactylifera) are frequently desired by his higher-end clients. ?We installed close to 2,000 date palms last year. That?s a lot. An installed date palm is a $3,000 item. We have a project going right now that calls for 278 of them,? he reports.
Micetic uses very few evergreen shrubs, but often uses Goldwater (Pinus brutia var. eldarica) or Mondale (Pinus Eldarica) pines around shopping centers.
Terrain Systems installs a lot of drought-tolerant plants in front-yard, residential xeriscapes. Groundcovers include lantana (Lantana camara), myoporum (Myoporum parvifolium) and wedelia (Wedelia trilobata). Salvia is a popular accent plant, as well as the indigenous brittle bush (Encelia farinosa), which he says looks like a miniature sunflower (Helianthus annuus). Due to economics, Micetic typically keeps flower beds? color to a minimum. Decorative grasses, including drought-tolerant deer grass (Muhlenbergia rigens), are used in his xeriscapes, but seldom a cactus, other than a saguaro (Carnegiea) or some pencil cholla cactus (Cylindropuntia arbuscula), because without adequate drainage, they become waterlogged. For turf, he goes with hybrid bermudagrasses (Cynodon dactylon ?hybrid?), Midiron or Santa Ana, primarily sod. In parks, he often combines sod and seed, using a native seed mix of grass and wildflowers.
Micetic says his single, most expensive line item is rock, used in his area for dust control and aesthetics. He says it runs in the neighborhood of $60,000 to $70,000 per month.
Xeriscapes typically have drip irrigation available. Micetic notes that a city ordinance in Phoenix requires an automatic irrigation system for any commercial landscape. ?It?s good for the entire community. That?s why we have this lush oasis habitat in the desert. Without irrigation, they would die,? he says.
In San Antonio, where residential water use accounts
for 65 percent of the city?s water consumption, at least 35 percent of that is for outdoor watering. Hence, the San Antonio Water System (SAWS) offers customers 10 cents per square foot, for
planning and installing a watersaver landscape, with a minimum conversion of 1,000 square feet ($100), and a maximum rebate of $500 for 5,000 square feet. If more than 50 percent of the entire yard
is planted in turf, the customer receives half credit.
?We also use regionally-adapted plants, such as salvias. Greggii (Autumn Sage) is a real favorite here,? says landscape architect Dixie Watkins III, who founded his business fourteen years ago. Native plants are playing a greater role in environmentally-based projects. Watkins is currently engaged in one along Leon Creek for the SAWS?conservation department. The venture is funded by a 310 grant from the Environmental Protection Agency (EPA) and the Texas Natural Resources Conservation Commission (TNRCC).
?We?re just now developing a palette and drainage retrofits. I?m working with an urban biologist. We?re going back with our best management practices, taking a fresh look, not just compass orientations, but soil moisture regimes. Bexar County has a number of different types of soils. That is being looked at with different layers of wildlife habitat, slope control, erosion and filtration, as well as water quality and water quantity issues,? he says.
Most recently, emphasis has been on making the rocks, boulders, soils and plant materials work together, and using the natural elements rather than concrete to heal the scars between drainage outfalls and natural greenlands.
?It?s fun stuff,? says Watkins. ?We design and install with mezic and xeric plants and understory trees. Those would include persimmon (Diospyros texana), and perhaps plain-leaf sumac (Rhus microphylla), which is good for rooting aspects. A whole different mixture you could use would be Texas Mountain Laurel (Sophora secundiflora), skunk leaf sumac (Rhus trilobata) and agarita (Mahonia trifoliata)?some of the earlier harbingers in spring. We like to use bald cypress (Taxodium distichum) for root integrity, but we don?t have the luxury of that much water here.?
Landscape Management Company in Gainesville, Georgia, is another firm that does restorative contract work for various entities, drawing from a number of native trees
and plants in the process.
?You use what is available, and unless they are tried and true and tested, you may really go out on a limb. We find ourselves substituting,? says Perkins. ?We don?t use a substantial number of natives in residential landscapes other than the native type of azaleas (Rhododendron simsii) and rhododendrons (Rhododendron sp.).
Some of the native trees, especially in the Lakeland area, would include native red maple (Acer rubrum) and serviceberry (Amelanchier). The river birch (Betula nigra) is just a plain old common birch, but we design and install using a commercial hybrid. We use wax myrtle (Myrica cerifera), yaupon hollies (Ilex vomitoria), and the newer natives. Things like fringetrees (Chionanthus virginicus) and sweet shrubs, on a large commercial scale, are still very limited. Dogwoods (Cornus florida) are native to us, but sometimes they are so temperamental, even though they are available in the commercial market. Transplanting one is a feat in and of itself. Dogwoods are very susceptible to drought as well. Duplicating nature is difficult.?
How many times, when we travel to a different part of the country, do we admire the plant material that is native to the area? Native plant landscapes and xeriscapes will grow in popularity, especially as water becomes increasingly scarce. Vive la difference!