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April 1997

Xeriscaping at the Foothills Lab: A progress report

Adam's needle, banana yucca, dwarf fountain grass, pink woolly speedwell. These are some of the plants in the NCAR xeriscape gardens--islands of environmentally appropriate vegetation in the middle of the Foothills Lab parking lots. In honor of Earth Day, Staff Notes Monthly takes a look at the islands' evolution from water-guzzling, asphalt-disrupting problems to oases of environmental stewardship.

After UCAR purchased the Foothills Laboratory complex in 1990, renovations to adapt the space to NCAR's needs took about two years. But the interior was not the only part of FL that needed modification. Facilities Support Services (FSS) acquired responsibility for a new landscape unlike the relatively natural environment of the Mesa Lab. The grounds and parking areas had landscaping more suited to the water-abundant climate of the eastern United States than to Colorado's high plains environment.

It wasn't long before Rich Johnson of Outside Maintenance discovered that the cottonwood trees and Kentucky bluegrass on the FL parking lot islands presented a mix of problems, and an opportunity. The nursery-bred cottonwoods were planted when the lab was built in 1982. According to Rich, they were considered a good choice years ago because they grow quickly and are native to riparian areas of Colorado. However, in the middle of the parking lot, away from the banks of a waterway, their shallow root systems were spreading, pushing up through the concrete and tearing up the asphalt. When it was time to mow the water-thirsty bluegrass, the mower blades would get caught and damage the gnarled tree roots. The soft wood produced by the rapidly growing trees was weak and vulnerable; branches torn off by windstorms and early snows presented safety and maintenance problems.

Meanwhile, the Environmental Stewardship Committee was interested in conserving water and minimizing use of toxic lawn-care products. When Rich pointed out the problems with the cottonwoods, FSS director Pat Harris felt it was time to try something new. Rich had been investigating xeriscaping--the practice of landscaping with plants adapted to arid climates (xeros is Greek for dry). He thought the islands might make good testing grounds.

Rich had already created a pilot project at the east side of FL1. When renovation work disrupted the landscape near the east entryway, he used the opportunity to test drought-resistant plants in a terraced xeriscape instead of installing sod. The next area to acquire alternative plantings was Dedication Park, the courtyard with benches at the east end of the main-entrance shuttle loop created in time for 15 July 1992 ceremonies inaugurating NCAR's newest facility.

The islands in the visitor parking lot at the main (south) entrance presented a new challenge. Beginning in the fall of 1994, as the cottonwoods came down, Rich went in with a backhoe to plow up their extensive root systems. The next task was soil preparation, "the most important thing you can spend your effort on," according to Rich. He did a lot of mulching, trying to break up the dense clay soil. (For the island at the east end of the visitor lot just now being transformed, Rich simply rototilled the existing soil so he can compare it with the performance of the mulched islands.)

Now in their third season, the islands are home to flowering daffodils, crocus, and tulips and a wide variety of shrubs, bushes, and ground cover. Slow-growing burr oak, catalpa, hawthorn, ash, and Kentucky coffee trees are beginning to take root. (Planting a variety of trees reduces vulnerability to species-specific diseases.) Carefully placed buff-rock and moss-rock borders give the islands visual texture and terrace the soil.

The buffalo grass stays dormant until the weather turns warmer. Special porous mesh material allows water and air to reach the soil while inhibiting weed growth. But weeds are still a problem, so Rich and Beau Charbonneau hand-pick and spot-spray them in the spring. Rich has cut back on routine use of herbicides and pesticides, not only on the xeriscape islands but also on the bluegrass surrounding the lab. Some of the trees have been sprayed for specific diseases, but this will be the first season in three or four years for broad lawn spraying. For Rich, reduced spraying and xeriscaping go hand in hand: "Being that we are an environmentally conscious institution, I thought we should try to set an example."

Rich Johnson and Beau Charbonneau. (Photos by Carlye Calvin.)

The island with FL's building sign and some of its neighbors came with a sprinkler system that has been converted to provide some sprinkler heads and some drip irrigation. New plants receive water once a week to help them get started; once established, they do well on natural rainfall alone. In contrast, the Kentucky bluegrass surrounding FL gets watered every two to three days, depending on the weather and time of year.

Visitors to the site will find crushed gravel paths to ease navigation. Handwritten signs identifying each plant fade out in the summer sun, so Rich is working on a schematic map to be placed on NCAR's Web site. A large version of the map is planned for the west end of the building sign island.

Rich has received master gardener certification from Colorado State University, read lots of literature, and shared information with the City of Boulder Water Conservation Office. When it comes to xeriscaping in Colorado, he'll tell you that "there are not a lot of examples around. We're learning as we go." The FL site was featured on a self-guided tour of xeriscapes in Boulder last year and will be included in the next edition of the Native Landscaping Guide of Boulder County, which is published cooperatively by the Boulder Energy Conservation Center, the city, and the county.

A thoughtful empiricist and meticulous craftsperson, Rich asks UCAR staff to be patient as the xeriscape gardens evolve. "It takes time and effort to get things right." Staff who want to learn more about the FL project or the potential for xeriscaping at home can contact Rich at ext. 1129. Copies of the Native Landscaping Guide of Boulder County are available from Paul Lander, Boulder Water Conservation Office, 413-7407. •Zhenya Gallon

The NCAR site is outlined in white in this aerial view of Table Mountain, photographed in the early 1960s, before the access road or any buildings had been constructed.

Helping nature on the mesa

When plans to build the Mesa Lab were being considered in 1960-61, Earth Day was still a decade away, but preservation of the beauty and sensitive ecology of the mesa was foremost in the minds of its developers. In a 1961 prospectus, UCAR president and first NCAR director Walter Orr Roberts described the intention of the NCAR board and staff to develop "a site plan and a laboratory design suitable to the high task of the center and worthy of the natural setting in which it is to be placed." Walt and his colleagues understood the site's unique features and put considerable effort into discovering how best to preserve them. The prospectus promised "preservation of the natural beauty of the site, a minimum disturbance of topsoil and vegetation, [and] landscaping compatible with existing vegetation."

Installing acres of irrigated lawn was never an item for discussion. Instead, in March 1963, a few months before construction began, NCAR business manager Robert Low wrote to Donald Hervey in the College of Forestry at Colorado State University to ask what could be done to restore the site's natural vegetation once construction was completed. In 1961 CU biologist Bill Weber had cautioned that the natural cycle that established the mesa's particular flora had been lengthy, and there was almost no topsoil to work with. Traditional methods of scraping off vegetation and top material and spreading it over finished areas would likely result in a giant weed patch, as had happened at Rocky Flats. Bob Low asked Hervey which kinds of grasses would best blend in with the undisturbed areas and require minimal or no irrigation.

Hervey's four-page report detailed his specifications for restoring the building site, utility cuts, and the banks of the new road cut. To help reestablish ground cover, he suggested mixing native grasses with nonnative varieties. Ernest Shapard of Shapard's Gardens (then in Boulder, now located in Longmont) was called in to advise and carry out the restoration in the spring of 1965. In consultation with CSU, he created the seed formula used at the Mesa Lab. Dubbed the "NCAR Mix" and sold for years at Shapard's as "Foothills Mix," the recipe called for:
Canada blue grass (4.70%)
crested wheat grass (22.63%)
western wheat grass (7.19%)
durar hard fescue (7.91%)
slender wheat grass (14.34%)
Kentucky blue grass (9.84%)
sand drop seed (.96%)
blue grama grass (4.32%)
annual rye grass (14.72%)
sheep fescue (4.76%)
inert ingredients (8.63%).
In Boulder, McGuckin Hardware sells a Foothills Mix that varies only slightly from this recipe.

The tradition of environmental responsibility that began with the selection of Table Mountain as the Mesa Lab site continues through the work of the Environmental Stewardship Program. Contact Gaylynn Potemkin, ESP chair, at ext. 1618 or potemkin@ucar.edu, or visit their Web site. •ZG

Special thanks to Diane Rabson of the NCAR Archives for providing background and documents on which this article is based.

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Edited by Bob Henson, bhenson@ucar.edu