McConnell Arboretum & Gardens in Redding, California

A Living Laboratory for Plants

By: David A. Laws
David Laws

David A. Laws enjoys combining his interests in gardening, technology, and travel by photographing and writing about them from his…

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Drought tolerant, low water use plants native to the world’s mediterranean climate regions beautifully address challenges facing the McConnell Arboretum & Gardens.  Photo: Daderot/Wikimedia Commons

Drought tolerant, low water use plants native to the world’s mediterranean climate regions beautifully address challenges facing the McConnell Arboretum & Gardens. Photo: Daderot/Wikimedia Commons

Searing heat, freezing cold, foraging deer, extended drought, raging forest fire, and a popular pedestrian highway—dealing with any one of these conditions would be a daunting challenge for a botanical garden. Since opening in 2005, horticulturists at the McConnell Arboretum & Gardens at Turtle Bay Exploration Park in Redding, California, have successfully confronted all of these threats to create a popular public space that delights visitors and is beloved by residents.

The citizens of Redding have demonstrated their ability to tackle projects that are bold for a community many times their size. Designed by world-renowned Spanish architect Santiago Calatrava, the distinctive $24 million Sundial Bridge, which opened in July 2004, has given the city an identity recognized far beyond the Central Valley. For a regional garden, the nearly $9 million investment in McConnell Arboretum & Gardens appears equally ambitious.

An early photo of the Sundial Bridge at Turtle Bay crossing the Sacramento River.  Photo: courtesy of the Redding Convention & Visitors Bureau

An early photo of the Sundial Bridge at Turtle Bay crossing the Sacramento River. Photo: courtesy of the Redding Convention & Visitors Bureau

Both the bridge and the gardens are located in the 300-acre Turtle Bay Exploration Park flanking the north and south banks of the Sacramento River near downtown Redding. The south bank complex includes a museum, a bird sanctuary, wildlife education areas, a new Sheraton Hotel, and a walkway to the bridge. On the north side, the arboretum and botanical gardens cover 200 acres of riverbank and oak savannah bluffs. The 28-acre botanical garden of predominantly drought-tolerant plants, many of them previously unfamiliar to local gardeners, is fenced within the arboretum.

McConnell Arboretum & Gardens at Turtle Bay in Redding, California.  Photo: Daderot/Wikimedia Commons

McConnell Arboretum & Gardens at Turtle Bay in Redding, California. Photo: Daderot/Wikimedia Commons

The Gardens

In “A New Garden for the Northern Central Valley” published in the October 2005 issue of Pacific Horticulture, horticultural manager Lisa Endicott expressed her hope that “people will take a closer look at the exciting new plants.” I met with Lisa in late September 2016, to learn how the garden has fared over its first decade and to find out if local nurseries and homeowners had responded to her advocacy of drought-tolerant species.

Summer blooms greet visitors at the west entrance to the botanical collection.  Photo: courtesy of McConnell Arboretum & Gardens

Summer blooms greet visitors at the west entrance to the botanical collection. Photo: courtesy of McConnell Arboretum & Gardens

Most pedestrian visitors to the botanical garden enter from the North Plaza at the base of the soaring 217-foot-tall sundial gnomon. A tree-lined lot offers shaded car parking at the west entrance on Arboretum Drive. A quarter-mile-long, 20-foot-wide boulevard cutting directly through the heart of the garden links the two entries. A woodland containing valley oaks, California sycamores, gray pines, and dense riparian habitat near the riverbank softens the utilitarian appearance of this roadway, which is mandated by the city for emergency vehicle access. The level, decomposed granite and gravel surface is popular with joggers, walkers, and garden visitors who appreciate easy access to more than a dozen themed areas.

Gardens representing all five of the world’s mediterranean climate areas—California, South Africa, southern and western Australia, Chile, and the Mediterranean Basin—are arrayed along both sides of the central pathway. According to Lisa, this is a tough garden that reflects the realities of the local climate and terrain by using “plants that look like they belong here.” Here, many species that typically thrive in full sun prefer a tree canopy that shades the understory from the fiercest afternoon heat. These include an allée of dwarf rosemary (Rosmarinus officinalis ‘Collingwood Ingram’), dense beds of golden-flowered Grevillea juniperina, and non-invasive ornamental grasses such as Lomandra and evergreen Miscanthus.

More sun-loving grasses fill much of the open space. Waving grasses, backlit by the lowering light, are a distinctive feature of the garden through late summer and fall. In an interview with Jennifer Jewell, MSNPR radio host of In a North State Garden, Lisa said, “We must have upwards of 50 varieties,” and “We might have more native California deer grass than anywhere in the world.” Deer grass (Muhlenbergia rigens) has proven useful in difficult conditions, such as on a slope near the Sundial Bridge. Lisa’s favorite meadow of blue wildrye (Elymus glaucus), a tufted perennial bunchgrass, failed in the heat, but is rapidly being replaced by creeping wildrye (Leymus triticoides) that snuck in with the blue wildrye seeds. “I guess we’ll live with that,” she sighed.

California live oak (Quercus agrifolia). Photo: Daderot/Wikimedia Commons

California live oak (Quercus agrifolia). Photo: Daderot/Wikimedia Commons

A Native Urban Forest funded by a grant from the Cal Fire Urban & Community Forestry Program is now in its third year. Volunteers wrap the trunks of an avenue of young valley oaks with expandable paper material each summer until the foliage spreads enough to shade tender bark. The recently refreshed Pollinator Garden at the west entrance, designed to attract birds, butterflies, bees, bats, and insects, now holds more than 80 drought-tolerant varieties. A brilliant display of scarlet California fuchsia (Epilobium canum ‘El Tigre’) spilled onto the path during my visit in September.

Two of the areas that are most popular with visitors who are less horticulturally inclined are the Children’s Garden and Celebration Garden. Designed for weddings, parties, and receptions, the latter’s small rooms display texture, fragrance, fruit, blue and white colors, and thirstier plants. In the shaded Children’s Garden, curving serpentine walls featuring turtles, butterflies, and local scenes form a wide bench around the Mosaic Oasis fountain and play structure that was designed by artist Colleen Barry.

Earthstone, a mosaic sculpture by Colleen Barry.  Photo: David A. Laws

Earthstone, a mosaic sculpture by Colleen Barry. Photo: David A. Laws

Art in the Garden

In addition to the Sundial Bridge, an extraordinary piece of functional art, examples of local work are displayed throughout the garden. Sounds of Water, a granite-spired sculpture and fountain in the Pacific Rim Garden, provides a refreshing oasis while promoting wise water use. Under nearby shade trees, miniature classical rock-filled landscapes by Chinese penjing master Qiao Hong Gen are displayed on elevated trays from May to November.

Earthstone is a 14,000-pound, abstract concrete form embedded with custom ceramic mosaic pieces by Colleen Barry. Unveiled by garden benefactor Lawrence B. Dillion in 2016, the textured surface evokes leaves, stones, fossils, bark, and creatures that are endemic to the area.

A monumental earthen cone planted with native grasses provides a striking focal point in the Sustainability Garden.  Photo: Marion Brenner

A monumental earthen cone planted with native grasses provides a striking focal point in the Sustainability Garden. Photo: Marion Brenner

Waving ornamental grasses and a rill flowing with water add movement to the Sustainability Garden designed by Lutsko Associates.  Photo: David A. Laws

Waving ornamental grasses and a rill flowing with water add movement to the Sustainability Garden designed by Lutsko Associates. Photo: David A. Laws

A striking example of a landscape architect’s work is in the arboretum west of the botanical enclosure. In 2008, Lutsko Associates created a 10-acre Sustainability Garden to complement the rammed earth walls of the McConnell Foundation’s administrative office campus. A native grass-covered cone of soil that resulted from site development echoes the distant volcanic peak of Shasta Bally Mountain. Water flowing in a series of stepped channels suggests a salmon ladder as it descends to a bioswale through multiple levels of a mellow, caramel-colored stone hardscape. Except for a wide circle of moisture-loving Lombardy poplar (Populus nigra ‘Italica’), the plants chosen for the site are drought tolerant.

Winding paths bordered by colorful perennials invite pedestrians to explore the gardens.  Photo: courtesy of McConnell Arboretum & Gardens

Winding paths bordered by colorful perennials invite pedestrians to explore the gardens. Photo: courtesy of McConnell Arboretum & Gardens

Facing Threats 

Selected for their suitability to a Sunset Zone 9 region, the original plantings have been thoroughly tested during their first decade for heat and cold tolerance. During a recent cold winter with several 19°F days across the river in Redding, the garden registered 13°F. And on the late September afternoon that I arrived, a record high temperature of 104°F smashed the previous high of 100°F that was set in 2003. Most plantings in the mediterranean climate gardens have survived these conditions. Unfortunately, some collections of New Zealand flax (Phormium spp.), South African cabbage tree (Cussonia paniculata), and African sumac (Rhus lancea or Searsia lancea) were lost to a combination of poor drainage and extreme frost. Plants that are native to the Chilean coastal strip or high altitudes have been the least successful as a geographical group. Conversely, an evergreen winter’s bark (Drimys winteri) tree with distinctive red bark and clusters of creamy white, jasmine-scented flowers that struggled for years is now showing signs of vigor.

Plantings in the Mediterranean Basin garden.  Photo: Daderot/Wikimedia Commons

Plantings in the Mediterranean Basin garden. Photo: Daderot/Wikimedia Commons

Early on, the garden’s designer Mark Holland, noted that poor drainage in the river-deposited heavy clay silt would prove challenging. Overlaying a succession of cobblestone ridges in which soil varies from 1 to 12 feet deep requires local adjustment of the irrigation system. As plantings became established, water use across the garden was reduced to a low-maintenance level. Low water use is most notable in the Mediterranean Basin Garden where colorful displays of lavender, Phlomis, rockrose, rosemary, and yarrow thrive on a fraction of the original consumption and zero fertilizer. Soil amendment in a new Mexican Garden currently under development is being carefully matched to the moisture demands of the plants.

The gardens face threats other than drought, as well. Generations of deer raised in the gardens have been unfazed by motion-activated sprinklers. Fawns with water streaming off their coats found the Alstroemeria beds especially delectable. Applications of Liquid Fence, while effective, proved unpleasant for human visitors who didn’t appreciate the rotten egg aroma. Deer Off is currently the preferred repellant and is sprayed on sensitive plants every two weeks.

The most serious threat to the garden came on a hot August day in 2008. Fanned by 60-mile-per-hour winds, a fire devoured 100 acres of adjacent oak savannah and spread into the garden. Although the flames were doused quickly, they engulfed more than five acres of plantings. Hopes that several large gray pines would survive were later shattered by an especially cold winter that split protective bark and killed the trees. Understory Grevillea and whiteleaf manzanita (Arctostaphylos viscida) recovered quickly and few signs of the blaze other than scorched trunks remain.

Showy milkweed (Asclepias speciosa) in the pollinator garden.  Photo: courtesy of McConnell Arboretum & Gardens

Showy milkweed (Asclepias speciosa) in the pollinator garden. Photo: courtesy of McConnell Arboretum & Gardens

Economic downturns have threatened the garden as well. The recession that began in 2009 reduced garden funding. Now, a full-time head gardener and two part-time employees work the 28-acre garden alongside volunteers. Staffing is down from five gardeners that were employed shortly after the garden opened. Maintenance of the more than 200-acre arboretum and gardens consumed approximately $300,000 of Turtle Bay’s 2015 operating budget of $4.4 million. Much of this budget comes from generous donations by the McConnell Foundation. A $4 garden entry fee is collected on an honor system. Other income is derived from memberships and sales at the Arboretum and Gardens nursery. Under the direction of specialist Lynne Klocke, nursery volunteers propagate more than 90 percent of the garden’s new plants. Senior horticulturist Linda Russo also manages special propagation projects for local native habitat restoration.

Connected to Place

Reflecting on her 15-year tenure as horticulture manger, Lisa says, “I love my job and this garden. I have seen greener, more lush, and more manicured spaces in my travels, but few that are as compatible with their setting.” Even after years of long days helping to bring this garden to life, after retirement she plans “to continue as a volunteer as long as I am able.” Lisa is especially pleased with her goal of encouraging local nurseries and gardeners to use drought-tolerant plants and low-water-use varieties. Rockroses, California natives, and a wide variety of ornamental grasses are popular with customers. Mark Holland’s vision of the gardens as a living laboratory for North State gardeners was prescient.