When it comes to mulch, green is the new brown.
Instead of spreading bark, peat or straw over your planting beds, consider planting a living mulch that will spread itself over your bare soil, keeping it cool and moist while also adding a lushness that is more attractive than conventional alternatives.
Some prominent landscape professionals are embracing the idea, saying real plants are more attractive and better for the environment.
“Bare ground is an abomination against nature,” said Curtis Short, an aesthetic pruner and gardener in Sonoma County who has long been a cheerleader for the virtues of mulch in its many forms.
Green mulch was a hot topic at Pacific Horticulture’s “Changing Times, Changing Gardens” summit in Santa Rosa last fall. Thomas Rainer, a landscape architect in Washington D.C., who has designed projects for the U.S. Capitol grounds, the Martin Luther King, Jr. Memorial and the New York Botanical Garden, devoted his keynote address to the concept.
Rainer advocates creating a meadow that carpets the lower several inches of your entire landscape, while an arrangement of larger, discrete shrubs, trees or large, stout perennials, flourish above. Good bottom story plants in this region include anything from California poppies and society garlic to bleeding heart, snowberry and redwood sorrel.
Short came away a convert.
“I admit I am a big proponent of using mulch chippings, but I see them as a way to feed soil and defend against weeds while more desirable plants take hold,” he said. “I never intend a mulched area to remain plant free unless there is good reason for it to remain open.”
While more and more homeowners are wisely ripping out their lawns, they’re replacing them with landscapes that tend to be filled in with a lot of bark and pebbles.
“These are not ideal lawn substitutes because the world is a better place when ground is covered by a mulch of plants,” Short said. “If you have ground that is not paved with concrete, flagstone or pavers, then plant it. Those plants will sequester carbon, release oxygen, out-compete weeds, create habitat, improve the soil and beautify our world.”
Sherrie Althouse, the co-owner of California Flora Nursery in Fulton, said the idea makes sense on many levels, including weed suppression.
“To fill in with desirable plants that have traits you enjoy makes more sense than allowing weeds to come in that are opportunists that will take over the whole place,” she said. “As a gardener you get to be the one that makes the choice.”
Rainer has pointed out that plants are social creatures that in nature, live in communities. And yet so many gardens are filled with plants installed in isolation within what he has described as “a sea of mulch.”
A layer of living green material can also protect the soil from erosion, particularly on slopes, said Diana Douch of Artemis Design and Gardens in Sonoma County. And any additional water consumed by plants used as green mulch is offset by the moisture retained when the soil is shaded, which in turn provides a welcoming environment for lizards, worms and soil microbes that like cooler soil, she said.
Before planting, prepare the soil by digging it over to the depth of a fork and then, as she says “let the worms do the rest.” After that, add some organic soil amendment and dig it in for priority planting. After you have planted, add another 2-3 inches of mulch to suppress weeds while the new plants grow and spread.
Top picks for green mulch
“If you’ve already laid down rock mulch such as gravel, pebbles or decomposed granite, it is not to late to green it up,” Curtis Short said. “When planting, first clear a circle of rock down to the soil (including removing a large circle of any weed cloth). Make this clearing several inches wider than your plant’s root ball, till the soil underneath the planting spot and back fill around your plant with some loose soil so that it is level with the surrounding rock mulch.” His picks include:
Eschescholzia Californica or California poppy: Buy poppy seed in bulk from LeBallisters, Harmony Farm Supply or Western Farm Supply in Sonoma County and broadcast it over your rock mulch in the fall, ideally in October. No need to do any prep work. “Just wait for an eye-grabbing springtime display of orange,” says Short. “If you already have some poppy plants, cut the tops with their maturing seed capsules now and leave the debris on top of your rock mulch for about a week so seeds will be released to germinate later.”
Epilobium canum (aka Zauschneria Californica) or California fuchsia: Most varieties bloom orange to red flowers, but you can also find some in white or pink. All are super tough ground covers for full sun, with summer flowers that are hummingbird magnets. They will spread throughout rock mulch if encouraged with watering once every week or two throughout the first summer. Find them at California Flora Nursery and Emerisa Gardens.
Bulbine frutescens or jelly burn plant: Available with either yellow or orange delicate flower wands, this clumping succulent forms colonies several feet across by spreading rhizomes. The leaves are 18” tall and 1/4” wide green upright pointed fleshy blades. It weathers most Sonoma County winters and blooms almost continuously from early spring through fall. Short says it is so tough he’s seen it root into an asphalt parking lot. Give it some summer water in full sun although Short said he’s seen it do well with no irrigation where it gets afternoon shade. Find it at Emerisa Gardens .
Tulbaghia violacea or society garlic: This lavender-flowering cousin to the onion has foot foliage that is deer proof. It is more of a clumper than a spreader and can expand into colonies of 2-feet across or more, growing from resilient bulbs that allow it to survive nearly everywhere. Give it a little summer watering for the best leaves and flowers if planted in full sun. Short says they’re so resilient he once rescued some that sat uprooted in a dry rubbish heap for a year, and they thrived once replanted. Find them at Emerisa Gardens and R-Trees Nursery, among many other retail nurseries.
Aloe maculata (aka aloe saponaria) zebra or soap aloe: You can sometimes spot colonies of this succulent that have spread to many feet across on roadsides where they had been planted decades before then left untended, so it goes without saying that they are tough and drought tolerant. Attractive spotted rosettes of broad triangular toothed leaves grow to several inches and produce coral-colored flowers that can reach 3 feet tall. This is a great plant for what Short calls, your “hell strip,” that space between the sidewalk and curb where nothing else will grow. Find it at R-Trees Nursery.
Sherrie Althouse, who lives under the redwoods in Rio Nido, suggests these for a shade garden, all available at California Flora Nursery in Fulton.
Dicentra formosa or Western bleeding heart: It forms a lacy ground cover of ferny foliage, spreading widely in shady areas. Heart-shaped, pendulous pink flowers in the spring are an early nectar source for hummingbirds and bumblebees. As the soil dries the leaves fade and go dormant during the dry season, coming back with winter rains. Irrigation will keep them green longer into the season. This plant in the right spot spreads rapidly, competing well with tree roots. And it’s deer resistant.
Fragaria vesca or woodland strawberry: This ground cover spreads by stolons from a low carpet of foliage topped with pretty white flowers followed by small tasty fruits. It can be vigorous with irrigation but grows slower in dryer conditions.
Symphoricarpos albus ‘San Bruno Mountain’ or snowberry: A deciduous shrub with spreading roots, this form of snowberry stays under a foot tall. Small, rounded, bluish-green leaves on arching stems form soil holding colonies. The small white-to-pink urn-shaped flowers are highly attractive to pollinators. The showy white fruits that follow often hang around into winter on naked branches. Snowberry is adaptable and easy to grow, tolerating a range of conditions from sun along the coast to light shade. It likes moderate to occasional summer water but tolerates drought.
Oxalis oregana or redwood sorrel: This beautiful spreading ground cover is native to redwood forests and can flourish in deep shade, spreading by rhizomes to form carpets of clover-like leaves. Flower colors range from white to pink and bloom in spring. This is a good choice for woodland gardens where it competes well with tree roots. It thrives with summer irrigation but is drought tolerant in areas near the coast. Don’t confuse it with the noxious nonnative Oxalis that can take over gardens.
Diana Douch recommends these quick spreaders for sunny areas.
Baccharis pilularis ‘Pigeon Point’: This low-growing California native shrub grows 1-2 feet high and spreads 8-10 feet. It can go summer-dry once established in coastal areas, but inland it will require monthly irrigation for best appearance. It is lovely en masse, creating an evergreen, undulating form. Pigeon Point is one of the best California natives for erosion control, slope stabilization and fire resistance. The cover it provides is valuable for ground-nesting birds. Find it at California Flora Nursery
Arctostaphylos “Carmel Sur”: This California native is a dense evergreen ground cover that grows to 2 feet and spreads 6 feet. It grows from late winter into spring and is a brilliant green. It is one of the best manzanitas for weed and erosion control and spreads quickly. It tolerates heat, clay soil and irrigation. Find it at California Flora Nursery.
Festuca rubra: This is a California native perennial grass that forms tufted drifts of fluctuating, finely textured form. It can be used as an easy and low-maintenance lawn alternative. Soft and inviting to the eye, it thrives with low to moderate water and in full sun to light shade. Find it at California Flora Nursery.
Geranium x cantabrigiense “Biokovo”: A perennial native to Croatia that grows from rhizomes, forms a mat of aromatic foliage and blooms spring and throughout the summer. It has white flowers with a flush of light pink and grows 6-10 inches tall in sun or shade. It tolerates drought but looks best with moderate irrigation. Find it at R-Trees Nursery and Emerisa Gardens.
Cistus salvifolius or Rock Roses: This evergreen Mediterranean shrub is low-growing to 2 inches tall and 6-8 inches wide. Its spring-blooming white flowers with bright yellow centers show nicely against grey-green foliage. It’s drought tolerant in full sun and does well in difficult-to-garden areas. Find it at R-Trees Nursery, Emerisa Gardens.
Curtis Short: Curtisshortexpertpruning.com or email@example.com
Diana Douch, Artemis Design: 707-360-8885 or Artemis65design@gmail.com.
California Flora Nursery: 707-528-8813 or Calfloranursery.com. 2990 Somers Street, Fulton.
Emerisa Gardens: 707-525-9644 or Emerisa.com. 555 Irwin Lane, Santa Rosa.
R-Trees Wholesale Nursery: 707-586-1137, 4650 Arlington Ave,, Santa Rosa,
Harmony Farm Supply & Nursery: 707-823-9125, Harmonyfarm.com. 3244 Gravenstein Highway N., Sebastopol,
LeBallister’s Seed and Fertilizer: 707-526-6733 or firstname.lastname@example.org. 1250 Sebastopol Road, Santa Rosa
Western Farm Center: 707-545-072121, westernfarmcenter.com. 12 W. 7th St., Santa Rosa.