The fact that even the multi-billion dollar petroleum industry tries to market itself as ‘green’ (BP and Exxon come to mind) suggests the concept may sliding towards self-parody. I’ve even heard a dentist office market itself as ‘green.’ Although few now deny that converting to a sustainable economy is a laudable, even necessary goal, the idea that a product by itself can be ‘green’ is a fallacy. The parameters of a truly sustainable economy extend beyond making an informed purchase, to include a commitment to maintain that purchase. A ‘green’ dentist, in principle, would have only clients who floss regularly.

On the face of it, what could be a greener industry than landscaping? In the San Francisco Bay Area, the standards of ‘bio-friendly’ gardens are easily met: drought-tolerant plantings, freely-flowering perennials and shrubs for pollinators, organic fertilizers and pest control. No one would admit to being ‘opposed’ to butterflies and flowers, anymore than they would admit to being opposed to motherhood and apple pie.

A few years ago, I had a visit to my home in El Cerrito by a candidate for mayor. She informed me that she stood for honesty and integrity in government. When I said, “Oh, I’ve always taken the other side of that issue. I support graft and corruption,” the satire escaped her. The same point applies to landscaping. Why, if water conservation and habitat promotion are so universally recognized as good, are most commercial and residential landscapes still ‘Old School’ with water-gulping big lawns that are chemically maintained?

For most Bay Area landscapers, a green garden design is straightforward: use plants of Mediterranean-climate origin, water them with a drip system and cover all beds in a thick layer of mulch. Only natural fertilizers are applied, and pests are treated non-chemically. But if all this is beyond controversy, why is it not standard industry practice, instead of a precious marketing tactic? After all, these standards were articulated almost thirty years ago, a time when the ‘ecology’ movement coincided with one of California’s worst droughts on record.

The (surprisingly short) Life-Expectancy of a Garden

Most landscape design portfolios feature new gardens, rarely older than two years. That’s the garden that people fall in love with. Just as there are no ugly babies, a young garden is almost always pretty. But what becomes of those lush gardens in a five or ten years? Who maintains them?

The ‘green’ landscape’s natural appearance may suggest little maintenance is needed, but even a natural garden looks best with skilled, timely care. During the winter ‘dormant’ season perennials should be trimmed back hard, the drip lines re-laid, and more mulch added. For a large garden, this work can require several days work by a crew of skilled gardeners, so it is costly. And although plants happily grow wild, most homeowners desire a tidy appearance, with regular cleanup throughout the year. Owing to the erratic schedules of most artisan gardeners, whose small businesses are subject to the vagaries of the climate and time demands of larger projects, many have a reputation for unreliability.

Lacking a simple garden maintenance protocol, the dry border garden rarely fares well under the care of the ‘hedgey-edgey-mowey-blowey’ gardener, yet many homeowner’s ultimately choose this type of service because it is inexpensive and reliable. Under this regime, everything that can’t be mowed is sheared into geometric solid shapes. Every particle of mulch is blown into the ether. Any flowers that might emerge are shaved off on the next visit. The drip system is left untouched, except for occasional owner-requested repairs. Trees are left leaning on their stakes like a criminal being frog-marched to jail.

Eventually, a few species start to dominate the border, and shrubs and trees that were closely planted ‘to fill in quickly’ are now merging into each other, pushing aside the smaller plants, and creating too much shade to support sun-loving perennials. Those cute little tree ‘puppies’ adopted five years ago have now grown into Great Danes, and the New Zealand flax ‘dwarf’ varieties have taken on the proportions of a Triceratops.

During the dry summer months, many plants look bedraggled, so more watering time is added. New plantings are attempted, but rarely thrive. Periodically more mulch is applied, but the soil underneath is dry and crusty; often occupied by huge colonies of ants. Even though just one or two weeds were missed, their seeds begin a slow march through the garden. Bermuda grass mysteriously beings to appear, and no amount of pulling can eradicate it. The garden seems to have permanently acquired the look one has just before one gets a haircut: misshapen and disorderly.

A Garden’s Fifth Birthday

The best time to evaluate the ‘green-ness’ of a landscape is not just after it has been designed and installed, but five years later. By the time the garden is five or six years old, it may already need replanting. Few people budget for a landscape replacement, since it was conceived originally as a construction project, to be undertaken with the same frequency as a bathroom remodel or a replacement roof.

Watering Your Garden

A quick measurement that is almost never made is actual water use. A drip system can waste a tremendous amount of water if it isn’t properly maintained and programmed. In the heavy clay soils that predominate in the Bay Area, a drip emitter left in one location will often start to ‘tunnel,’ wetting only a narrow column of soil, leaving most of the root horizon dry. Increasing the run- time only compounds the problem because the extra water travels deeper, away from the surface feeder roots.

Mulching Your Garden

Commercial mulches, usually redwood or cedar, are the product of highly destructive industrial logging practices, so are never good candidates for a ‘green’ garden. Made from processed bark, these mulches do help hold water in the soil, but unfortunately, also form a hydrophobic layer that inhibits water penetration during rainfall or irrigation. Decades may be required before they break down into the soil, so they do not add organic matter (tilth) to the soil, nor do they add nutrients.

Garden Structures (Decks, Arbors, Patios - Hardscaping)

Surprisingly, even ‘hardscape’ elements often show signs of decay as soon as five years after installation. This is particularly true with wooden structures which, nominally discouraged in a sustainable landscape, are often built as necessary exceptions. Decks are probably the worst offenders; the impulse to ‘deck first and ask questions later’ is frequently indulged by the landscaping industry, especially since so many ‘recycled’ deck products are available. But the fact remains that decks are a perishable and fire-prone feature in the landscape that should be used only when the grade precludes alternatives, such as patios. In the vast majority of cases decks aren’t necessary.

An arbor built from certified sustainably-harvested redwood can literally start to be consumed by the vine that was planted on it five years earlier. Although plant/lumber contact inevitably results in decay, wood from young trees typical of certified lumber simply does not have the decay-resistant properties associated with older trees of the same species. If a thirty-year old tree becomes part of a structure whose lifespan is only five years, it doesn’t matter what the label said when the lumber was purchased: precious forest resources have been wasted.

And what about the beautiful flagstone patio? If the patio was laid on sand, with plantings in the interstices, the stone itself may have started to decompose. This isn’t what one expects from a rock, which seems the embodiment of timelessness. Certainly the carbon footprint required to ship stone thousands of miles is a blemish on the goal of sustainability. From the perspective of local geography, native stone tells a story about the landscape. Imported stones are like a geologist’s sight gag; the only story they can tell is “I came off a truck.”

Garden Water Features

Although immensely popular as part of a garden’s design, ponds, fountains and waterfalls inevitably present maintenance challenges. Algae and mosquito control present on-going problems, and the sump pumps that run these features require replacement with surprising frequency. Many homeowners eventually abandon such features, requiring that they be filled or punctured.

Replanting Your Garden

Although many landscape contractors are loath to inform their clients, perennial gardens need to be replaced at least as frequently as the house itself needs to be painted. But while a painter does the entire house, landscape replanting must preserve the longer-lived elements such as large shrubs and trees. Replanting a garden is in some ways more of a challenge than the original planting, and is often less successful.

In comparison, the ‘old-school’ landscape typically ages less perceptibly, and often looks about the same on its fifth birthday as it did when it was newborn. Although usually irrigated with spray type sprinklers, short run times mean that a lawn-intensive garden isn’t necessarily a water guzzler. Of course, this also implies a shallow root system; old school landscapes would suffer irreparable damage if water were withheld entirely, so are rarely ‘drought-tolerant.’ Moreover, these garden are never candidates for butterfly or bird habitat, since the flowers required for forage are lopped off with hedge pruners. In truth, the bright green lawns are but a veneer of growth, requiring synthetic fertilizers to stay ‘chem-lawn’ green. While old-school gardens cannot be considered environmentally sound, if lush tidiness is the criterion, they may be more ‘successful’ than the eco-friendly gardens. They also tend to be inexpensive to maintain because the gardening process is largely mechanized.

Seven Steps for a Long-Lived ‘Green’ Garden

Natural gardens will be longer lived and more cohesive in appearance using this simple protocol. With a little patience, even your mow-blow-and-go gardeners can probably be trained to do this work. Or better yet, do it yourself!

1) Don’t overplant. Good garden design should space plantings according to their natural habit. This is especially true of trees. Remember, a small tree still grows to forty feet!
2) Don’t let weeds go to seed – EVER!!! As long as seeds aren’t being blown in from neighboring properties, weed seeds will have been purged from the soil in two to three years, and you will spend very little time weeding.
3) Water Wisely: Lift and relay drip lines every other year & set your irrigation controller for infrequent watering with multiple start times. Make seasonal adjustments by changing the frequency, not the duration of the runtime. Audit the irrigation system, to calculate how much water is actually being used. The results will surprise you, and suggest immediate steps for water conservation that will not stress your plants.
4) Replant only in the spring or late fall, when the soil is uniformly moist.
5) Consider using locally manufactured paving surfaces such as clay and concrete brick, or gravel, and build decks and garden structures sparingly. Wooden structures should be cleaned to remove plant debris every year.
6) Cut back perennials and shrubs in late fall, apply nitrogen rich compost. You’ll have to rake the mulch aside to apply the compost, then re-lay the mulch. Soil microbial action will have the nutrients ready and available for the spring flush of growth.
7) Mulch in spring with arborist’s wood chips, not bark mulches. This is the time to check your irrigation system for leaks.