The Evolution of a Native Garden

By: Katherine Greenberg

Katherine Hayes Greenberg is a garden designer with a passion for California’s native plants. She is a past president of…

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Deer grass (Muhlenbergia rigens), hummingbird sage (Salvia spathacea), and manzanitas (Arctostaphylos) edge the driveway to the author’s Lafayette home; coast live oaks (Quercus agrifolia), planted at the garden’s start thirty years ago, now completely enclose the property. Photographs by Saxon Holt

Deer grass (Muhlenbergia rigens), hummingbird sage (Salvia spathacea), and manzanitas (Arctostaphylos) edge the driveway to the author’s Lafayette home; coast live oaks (Quercus agrifolia), planted at the garden’s start thirty years ago, now completely enclose the property. Photographs by Saxon Holt

“Mine is a contemplative garden, and the repetition of forms, colors, and textures brings a mood of serenity that is more important to me with each passing season. The work of the garden adds to my pleasure in it, with the rewards far exceeding the demands it makes on me. It will not be complete in my lifetime, but will continue to develop, the oaks maturing to provide satisfaction and pleasure for my grandchildren as great as was mine in planting them.”
Katherine Greenberg, A Garden Shared, Pacific Horticulture, Winter 1995

Creating a native garden has proven to be more challenging and more rewarding than I ever could have imagined when I began thirty years ago. When we acquired the 1.3-acre property on a Lafayette hillside, it was covered with annual grasses, the original oak woodland having been cleared for agriculture early in the twentieth century. The grasses were removed when the site was graded for construction; the remaining vegetation consisted of oaks, bays, walnuts, buckeyes, and willows, all growing along a creek at the base of the slope. I envisioned a naturalistic garden, with spaces designed for outdoor living, trees for shade, and paths throughout.

Taking advantage of the property’s natural contours, we sited the house mid-way up the slope, with rooms opening to decks and terraces on two levels. A redwood pergola frames the entry and casts a changing pattern of shadows and light throughout the day. The main level of the house opens to a paved patio and pool terrace that are used for outdoor dining and entertaining. A path from the pool area leads to a gravel terrace on the lower level, which overlooks the creek. Faced with the challenge of creating a garden after several years of drought and water restrictions, I decided to plant California natives that would thrive with little or no supplemental water once established.

The oak and riparian woodlands, chaparral, and grasslands of the surrounding valley, and the redwood forests of the East Bay hills inspired me to create a garden that would reflect the character of the natural landscape. Knowing that, one day, more homes would be built around us, we planted shrubs and trees to create a private, enclosed space with views of the hills across the valley and of Mt Diablo to the east. We left the property unfenced, with the exception of the pool area, to preserve the connection with the natural landscape and access to the creek for deer and other wildlife.

A sculptural specimen of Arctostaphylos pajaroensis, appealing in any season

A sculptural specimen of Arctostaphylos pajaroensis, appealing in any season

Trees First

In the first winter, I planted a number of coast live oaks (Quercus agrifolia) from small containers; they have since become mature trees that provide shade and shelter for people and wildlife. I also planted flats of dwarf coyote brush (Baccharis pilularis) to stabilize the slopes above and below the house, together with California wax myrtles (Myrica californica), coffeeberries (Rhamnus californica), manzanitas (Arctostaphylos), and toyons (Heteromeles arbutifolia). As the oaks have grown, I have replaced most of the coyote brush with species that tolerate dry shade, such as evergreen currant (Ribes viburnifolium) and native iris. Oak leaf litter makes a natural mulch under the trees; I have also used it to cover bare soil in other parts of the garden. Replenishing the mulch with tree chippings every few years has proven useful for conserving moisture, cooling the soil, and discouraging weeds throughout the garden.

The patio and path to the pool terrace

The patio and path to the pool terrace

We installed an automatic irrigation system before the initial planting to help the new plants get established through their first few summers. There are stations for both overhead and drip irrigation, but I operate the system manually, and only as needed. Watering sections of the garden once or twice a month in summer improves the appearance of plants, and the infrequent, deep watering promotes deep roots that can tap into underground sources of moisture during the dry months. I have modified the system over the years to direct water away from the oaks and to provide coverage for an evolving garden. I hand water newly planted areas, but some areas receive no water other than from the natural winter rains. Containers planted with dudleyas, sedums, and drought-tolerant perennials need to be watered once or twice a week in summer.

Hummingbird sage (Salvia spathacea) and purple sage (S. leucophylla), manzanitas (Arctostaphylos), and deer grass (Muhlenbergia rigens) against a background of native trees along the creek

Hummingbird sage (Salvia spathacea) and purple sage (S. leucophylla), manzanitas (Arctostaphylos), and deer grass (Muhlenbergia rigens) against a background of native trees along the creek

Living on a hillside adjacent to open space is appealing in many respects, but it comes with the ever-present threat of wildfire. Occasional irrigation helps keep plants hydrated to resist burning and improve their appearance. Some of the other steps we have taken to maintain a defensible space around the house include creating fire breaks around the perimeter of the property, controlling weeds, and pruning shrubs and trees to remove dead branches and to separate vegetation layers. Most native plants in California’s fire-prone areas are adapted to periodic fires, and a number of species will stump-sprout after a fire. I follow that model in rejuvenating toyons, coffeeberries, coyote brush, California wax myrtle, and native grasses, by giving them a hard pruning to stimulate new growth every few years.

The garden is not demanding in terms of maintenance. My approach has been to tend the garden on a seasonal basis rather than on a strict weekly or monthly schedule. After three decades of mulching with tree chippings and leaf litter, there are few weeds. I can weed the entire property in an hour or two by pulling out young weeds when they germinate, usually after the first autumn rains and again in spring when the weather warms. I plant only in the late fall, to take advantage of the cooler weather and winter rains to help young plants get established and reduce the need for watering. I generally add some soil amendment to the native clay soil to create a transition zone for roots of these young plants that have been growing in a container mix. Most pruning is done in the late summer or fall when the plants are dormant; the clippings are recycled as mulch.

The north side of the house retains more moisture, and here a grove of vine maples (Acer circinatum) has naturalized with Western sword fern (Polystichum munitum), wild ginger (Asarum caudatum), and Western bleeding heart (Dicentra formosa). I recently removed a small grove of redwoods on the east side of the house to open up this area to the morning sun and create an opportunity for planting to compliment the Western redbuds (Cercis occidentalis), toyons, and coast live oaks growing nearby. Drifts of deer grass (Muhlenbergia rigens), sages (Salvia), manzanitas, and California fuchsia (Zauschneria californica) border the driveway; I repeated some of these plantings on a sunny terrace below the house. The colors, textures, and scents of chaparral and woodland plants evoke childhood memories of hiking in the Santa Lucia Mountains in Monterey County, where I grew up.

For the first fifteen years, I focused on developing the garden around the house, leaving the overgrown creek area in its natural state. It was pleasant to hear the sound of running water, but access to the creek was impossible until we cleared away the dense thicket of blackberries and poison oak that covered its banks. I discovered wood ferns (Dryopteris arguta), snowberry (Symphoricarpos albus), and a wild rose (Rosa californica) growing under one of the bay trees, and I planted more snowberry, grasses, sedges, and irises in the steepest areas for erosion control. A stepping stone path and several well-worn deer trails provide access to the creek, which has become one of my favorite parts of the garden— pleasant in summer and dramatic in winter when the water rises after a heavy rainfall.

A small sitting area provides a peaceful retreat above the creek

A small sitting area provides a peaceful retreat above the creek

Wildlife and Other Pleasures

I enjoy watching the deer meander through the garden, stopping to rest under the vine maples and decks. Last spring, I was approached by a young fawn while I was working in the lower garden; it was a magical moment. All the plants in the garden are deer-resistant, except for young buckeyes (Aesculus californica) that need protection until they rise above the browse line. Browsing deer generally avoid grasses, ferns, irises, and plants with aromatic foliage; I have also found that most chaparral plants, with their tough, drought-adapted leaves, are deer resistant. They will sometimes eat the flowers of coral bells (Heuchera), but not the foliage. Squirrels and birds also live in the garden, and resident hummingbirds enjoy a continuous supply of nectar from manzanitas, salvias, and California fuchsias. Coyotes and mountain lions are occasional visitors.

A gravel path meanders through the lower terrace, with Iris ‘Canyon Snow’ in the foreground and vine maples (Acer circinatum) underplanted with Western bleeding heart (Dicentra formosa) in the middle right

A gravel path meanders through the lower terrace, with Iris ‘Canyon Snow’ in the foreground and vine maples (Acer circinatum) underplanted with Western bleeding heart (Dicentra formosa) in the middle right

The colors and textures of flowers, foliage, fruits, seeds, and bark sustain the garden through the year, and I have come to measure seasonal changes by certain events. The growing season begins with the autumn rains, and the manzanitas start blooming in November or December. On cold winter mornings, the garden shimmers under a layer of frost, and the silk tassel bushes (Garrya elliptica) are spectacular with their long, silver catkins. Redbuds herald the arrival of spring with their brilliant magenta flowers, and the native irises usually start to bloom in the first week of April. Spring-blooming Western bleeding heart and yellow-eyed grass (Sisyrinchium californicum), disappear in summer when the soil dries out but return with the winter rains.

The mahogany trunks of manzanita (Arctostaphylos) capture the eye year-round; here they provide background for Iris ‘Canyon Snow’, with Western bleeding heart (Dicentra formosa) as a carpet below

The mahogany trunks of manzanita (Arctostaphylos) capture the eye year-round; here they provide background for Iris ‘Canyon Snow’, with Western bleeding heart (Dicentra formosa) as a carpet below

In summer, the grasses are especially lovely. Autumn brings shorter days, the falling of acorns, and colorful foliage. The leaves of a ‘Roger’s Red’ grape (Vitis ‘Roger’s Red’) turn a brilliant red that rivals the fall color of poison oak; the feathery seedheads of mountain mahogany seem to glow in the autumn light. The silver grey bark of buckeyes is especially handsome in fall and winter against a background of dark green oaks. Manzanitas are attractive in every season, becoming more beautiful with age.

Working in the garden and observing its seasonal rhythms has been deeply satisfying, and it continues to be a source of pleasure. I can only wonder what discoveries the coming years will bring as the garden continues to evolve.

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The Evolution of a Native Garden