Part
Two - IMAGINING
A BETTER GARDEN
Imagine a garden
that rarely needs pruning, watering or fertilizing. One where
natural controls usually take care of pest problems before
the gardener even becomes aware of them. A peaceful garden
where the sound of blowers, power mowers or chain saws never
intrudes. Imagine a garden that also serves as a climate control
for the house, keeping it cool in summer and warm in winter,
a garden that traps rainwater in an attractive streambed to
deeply irrigate the trees and recharge the ground water, one
that provides habitat for wildlife and food for people. Imagine
a garden that truly works. This is the sustainable garden,
not barren or sacrificial, but as lush and beautiful as any
other without all the struggle and waste. Yes, it is just
that simple.
RELATIONSHIP
TO PLACE. No system that is placed in an unfavorable environment
will ever function successfully. Imagine a car in a world
with no gasoline. For the garden to work well, it must have
a finely-honed relationship to place. This means using plants
from appropriate climates that will survive for the most part
on what nature offers here and now, without subsidies from
outside. The natural soil will be hospitable to these plants
without the need for amendments and fertilizers. The natural
rainfall will be adequate to meet their water needs. The temperatures
will be agreeable to them without artificial modifications
of the microclimate. In other words, the garden will be adapted
to the carrying capacity of the land.
The hardscape
elements -- patios, walkways and the like -- will be placed
to take advantage of natural site features and microclimates
and will be built of simple materials, preserved in a state
of nature or nearly so, and that come from on site or nearby.
Southern California
landscape consultant Randall Ismay has calculated that 80
percent of the total cost of a garden over its lifespan is
maintenance labor and materials. Only 20 percent, then, goes
into its design and construction. That is often partially
attributable to unrealistic limitations on the designer’s
time and corner-cutting on the installation, but for the most
part, that 80/20 split is due to poor design that creates
a permanent maintenance burden far greater than is necessary.
It is through ignorance and carelessness that we create gardens
that are needlessly needy.
On another front,
most of the materials that go into the initial construction
of the landscape -- the concrete, lumber, stone and gravel,
and all the rest -- are either non-renewable or severely damaging
to their environment of origin. Consider decomposed granite,
a popular granular paving material that is attractive, inexpensive,
easy to install and permeable to rainwater. On those counts
it is a sustainable material. Yet, it is a soil type that
is strip-mined from once-pristine mountains.
It is unfortunate
that even proponents of sustainable landscaping have for the
most part ignored these off-site impacts and satisfied themselves
with creating gardens that, while they may be internally more
sustainable than conventional ones, pillage nature in the
course of their development and so are mere symbols of sustainability.
Indeed, their hypocrisy does violence to the idea of sustainability.
So, what’s
a better way? How does a sustainable garden actually work?
Here are some of the nuts and bolts of this evolving approach
to gardens...
BUT WHAT DOES IT LOOK LIKE?
In the old
xeriscape days, some people were afraid that the government
was going to come and take out their lawn and replace
it with cactus and rocks. Similarly, sometimes the idea
of a sustainable garden conjures up the image of a barren,
sad place that bears little relationship to the gardens
we know and love. What will you have to give up to gain
all these benefits? And what will it look like?
Well, the truth is that a sustainable garden can look
pretty much like any other garden. Sustainability is
independent of style. A Japanese garden can be sustainable.
So can an English border, a desert garden, you name
it. About the only thing you might have to forsake is
that acre of bluegrass in the front yard, but even that
could be more sustainable if it were replaced with a
yarrow lawn that uses half the water and requires mowing
only a few times a year.
Design your garden in whatever style you want, applying
the principles of sustainability as you go.
FIRST
PRINCIPLES
THE GARDEN
AS A SYSTEM. First and foremost, a sustainable garden is a system, just
as nature is a system, just as the human body is a system,
or for that matter a computer or an automobile or a toaster
oven. It consists of a complex of interrelated parts that
work together to create a functioning whole. Just as your
body remains alive and healthy due to the combined and harmonious
workings of the respiratory system, the circulatory system,
the endocrine system and all the rest, so a well-designed
garden will thrive when the insect system, the soil system,
the water system, the plant system, the drainage system and
many others are united in the common task of preserving the
integrity of the whole. Until the garden is designed and managed
as a system, our relationship to it will be primarily reactive
-- pulling weeds here, cutting back overgrown plants there,
watering when rainfall is insufficient for proper growth,
fertilizing when the native soil cannot bear the demands for
nutrition placed upon it by hungry exotic plants.
In the ancient
days of Japanese gardens, the designer would spend a year
on the site, watching the sun come up and go down again, every
day for a complete cycle of seasons. In this way, he was able
finally to understand the site well enough to make propitious
decisions in creating the garden. Today, we expect drive-by
design and we get the results we deserve.
HOMEOSTASIS. Nobody gardens nature. Have you ever wondered how that works?
A natural ecosystem exists in a state of active balance, remaining
stable until a triggering event changes the rules for a time.
A hillside of 20 year-old chaparral is an example of what
botanists call a "climax plant community." That
is, one that has reached its mature state and will remain
quiescent until it is disturbed, typically by wildfire. In
the climax condition, natural processes go on at a languid
pace -- weeds are shaded out by the dense canopy of Ceanothus
and toyon and sage, animal burrows are undisturbed by land
movement, plants gradually grow larger, insect populations
remain stable. Biologists define "homeostasis" as
"tending to maintain a relatively stable internal environment."
By designing a garden in which the plants are given a favorable
environment and room to grow, it is possible to create a homeostatic
condition that will serve the garden and the gardener well
for decades to come. In ignoring this principle. we create
gardens that are sub-climax plant communities, always in a
state of instability and therefore demanding of much care
and many resources.
INPUTS AND
OUTPUTS: A properly designed garden brings in fewer materials
for its construction and later for its care, and generates
little in the way of greenwaste, air pollution and other flows
to the outside world. Let’s think for a moment about
what comes and goes in the garden and how we might use less
without giving up any of the things we want.
INPUTS: BUILDING
MATERIALS: Consider first what is on the site that might
be utilized to advantage. Boulders can be rearranged into
an attractive retaining wall or dry streambed, for instance.
Soil can be molded into adobe blocks and those can be used
to build walls and other structures. Poles cut from that stand
of weedy Eucalyptus trees can be used as lumber for arbors,
fences and other garden woodwork. Similarly, whips pruned
from fruit trees can be woven together into an attractive
fence or trellis. The more you can use from on site, the less
damage you do to other places, the less pollution is caused
by trucking things in from far away, and the more money you
save.
In many cases,
materials of some kind will need to be brought in, especially
where structures and paving are involved. Turn to re-used
materials like railroad ties and broken concrete for your
first choice. If they don’t satisfy, select from materials
such as wood that come from renewable sources rather than
things like concrete that, though abundant, is non-renewable.
Also consider the "embodied energy" of the material:
the total energy that is required to produce and deliver the
material to you. Minimally-processed materials like lumber
and decomposed granite and gravel have a low embodied energy,
while things like brick, tile and concrete have a high embodied
energy. Don’t forget recycled materials -- plastic lumber
made from soda bottles and wood waste for example. There are
even ways to treat ordinary soil so that it will solidify
into a solid surface for walkways and roads. Finally, ask
where things come from and consider the impact your purchase
will have at the source.
INPUTS: WATER:
Conserve water by selecting plants that are native to a climate
similar to yours and that are known to be drought-tolerant.
Then provide a high-efficiency irrigation system such as drip
and learn to manage it properly, applying only enough water
to replace what is used up. Mulch all your plantings to reduce
evaporative losses from the soil, which can be significant.
Keep weeds down; they use water too. Consider planting less
densely to match the biomass to the carrying capacity of the
land. And of course, reduce lawn areas to only that which
you will use functionally, not ornamentally. Finally, where
it is appropriate and safe to do so, grade the site (and perhaps
build a dry streambed or percolation basins) to keep valuable
rainwater on the site. You might even consider installing
a cistern or other rainwater storage system to hold water
for use during the dry season. It is possible to have a full,
attractive planting with little or no supplemental watering
during normal rainfall years. Remember, nobody waters nature.
INPUTS: FERTILIZERS: Minimize the importation of fertilizers by selecting plants
that have low nutrient requirements and by fertilizing less
often at lower application rates. The best fertilizer is compost
that has been made from the very plants you’re fertilizing,
plugging another leak to the outside world. If you do have
a lawn, use a mulching mower that finely cuts the clippings
and blows them back down into the lawn, possibly the world’s
shortest trip to the compost pile. This is called "grasscycling"
and it really works.
INPUTS: PESTICIDES: Similarly, reduce the need for pesticides by planting pest-resistant
varieties and giving them satisfactory growing conditions.
Just as a person thrives with a good diet and plenty of exercise
and sickens in the absence of these things, so it is with
plants.
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When pests do
show up, practice a little benign neglect first. Think of
insects as co-inhabitants of the garden and remember that
for most pests there will be one or more kinds of predators
that can show up to keep the situation under control, at no
cost to you. If a pest problem begins to get out of hand,
import an appropriate ben-eficial insect as your first line
of defense. Beneficials are efficient and voracious and never
take a day off. Besides, learning about the relationships
between insects is as much fun as learning about plants. Only
if the beneficials don’t work (and please give them time
to do their job) then you might consider using a least-toxic
pesticide like insecticidal soap to knock down the population.
If a plant suffers
from chronic, disfiguring pest damage, consider replacing
it with a more appropriate species. Remember that of the hundreds
of garden chemicals, only a handful have ever been tested
for their effects on people, animals and the environment.
Besides, volatilization of garden chemicals contributes to
air quality problems.
There’s one
other secret about avoiding pest problems and that is to build
diversity into your plant palette. A mono-culture is much
more vulnerable to pests and diseases than a more complex
blend of things from many plant families.
INPUTS: HERBICIDES: Rather than applying herbicides, keep weeds down by avoiding
large expanses of low-growing ground covers that provide newly-germinated
weed seeds with a perfect environment for their development.
Use a drip irrigation system to keep the soil dry and therefore
unwelcoming to weeds. And mulch! Apply 3 to 4 inches of organic
mulch such as shredded bark or tree chips in all planted areas.
(Avoid letting mulch pile up around the trunks of plants,
and watch out for tree chips that contain lots of live seeds
or come from diseased trees.) Hand pull weeds when they’re
young, remembering the old gardener’s adage, "One
years’ seeds is nine years’ weeds."
INPUTS: FOSSIL
FUELS: Fossil fuels are used in the garden in some sneaky
ways. Of course, trucking materials from afar and making trips
to the landfill burns gasoline, but do you realize that many
chemical fertilizers and pesticides are made primarily from
petroleum byproducts? And of course, all that gas-driven equipment
uses petroleum, too. By planting right-sized plants that don’t
need cutting back so often, and by keeping their growth steady
with a lean diet of organic fertilizer and water, you’ll
be reducing the need to use all that equipment to cut them
back and haul them to the dump. (And don’t forget that
the soft new growth stimulated by fertilizers and water and
constant pruning makes the plants more susceptible to pest
infestations.) If you do need to prune, use hand tools rather
than power tools to eliminate one more source of fossil fuel
use.
INPUTS: TIME: A sustainably designed and managed garden will require much
less time to care for, because it is inherently stable. By
taking our cues from nature, we adopt the self-maintaining
character of the natural environment. A plant with room to
grow is one that doesn’t need to be pruned. A healthy
plant is one that doesn’t need to be sprayed. A building
material that is at or close to a state of nature (such as
a boulder) doesn’t need to be cared for like many highly-refined
materials systems (painted wood, for instance). And build
things to last so that you don’t have to replace or repair
them for a long time.
INPUTS: MONEY: A garden that uses so few materials and requires so little
care has just got to be less expensive, right? Right. Even
if the design and installation were to cost more (which probably
won’t be the case) the garden will still be much cheaper
to live with because there’s not much to do but enjoy
it. You’ll start getting a return right away and it will
continue for the life of the garden. In fact, one of the best
things about a sustainable garden is that it gets easier and
easier to live with, because it grows more and more stable
as it matures.
Compare that with a traditional garden that
demands more and more time and money as the trees and shrubs
get too big and need to be cut back oftener and oftener, as
the thirsty plants grow larger and need more water, and as
the poorly-built structures need constant tinkering to keep
them from falling apart. With a sustainable garden, you time
and your money are yours to enjoy.
OUTPUTS: GREENWASTE: The biggest item on the output side of the ledger is the trimmings
that leave your garden and go to the dump. Why have we accepted
this for so long? By and large, the only reason for trips
to the dump is that the plants don’t have enough room
to grow. Why plant a 20 foot tall plant when you want a 6
foot hedge? Why plant a 100 foot tall tree in a small patio?
And why, please tell me, put Juniperus tamariscifolia, which
grows up to 20 feet in diameter (you could look this up) into
a 5 foot wide parking strip? Yet these things are done all
the time, and not just by naive amateurs either. Yes, you
might have to wait an extra year for a right-sized plant to
grow to the size you want, but you’ll be saving yourself
a lifetime of cutting and hauling and looking like a fool.
So plant the right
size plants and then allow them to grow naturally, pruning
only to remove crossing or damaged branches. By fertilizing
and watering less, you also generate less greenwaste. Then,
recognize that greenwaste isn’t really waste at all,
but a valuable element in the garden system -- feedstock for
your composting operation. Chop it into small pieces, pile
it up (half green stuff and half brown stuff), squirt some
water on it and you’re on your way to a supply of compost
that can be returned to the garden to supply valuable nutrients
and beneficial soil microorganisms. Throwing away garden trimmings
is like burning dollar bills.
OUTPUTS: POLLUTED
RUNOFF: Fertilizers and pesticides leach out of the soil
with each irrigation and find their way into the groundwater,
streams and the ocean. If you don’t use them in the first
place, you won’t have to worry about this problem. And
if you grade the site to retain water, any bad stuff you do
have around will stay around.
OUTPUTS: AIR
POLLUTION: Similarly, the volatilization of fertilizers,
herbicides and pesticides into the atmosphere won’t be
a concern if you don’t introduce them into the garden
in the first place.
According to the
New York Times, a lawnmower operated for an hour emits as
much pollution as driving a car 50 miles. Far worse, in two
hours, a chain saw emits as many hydrocarbons as a new car
driven 3,000 miles! That’s not a typo. When the California
Air Resources Board added up the pollution from all the power
equipment used by the landscape industry, loggers and arborists,
it equaled that produced by 3.5 million cars driven 16,000
miles each. That doesn’t even count equipment used by
homeowners. Reduce this problem by cutting way back on your
use of gas-driven garden equipment, especially two-cycle engines
that power chainsaws, weed whackers, blowers and hedge trimmers.
Use hand tools or electric tools instead. And remember that
because your garden is designed to require little pruning,
you’ll be needing this equipment less anyway.
OTHER
CONSIDERATIONS
HARVESTING
FROM THE WASTE STREAM: We can go beyond merely minimizing
our consumption and waste. The garden can actually reduce
overall waste by harvesting materials from the waste stream.
Here are a few suggestions; with a little imagination you
can come up with more. Glean feedstock for your compost pile
from restaurants and grocery stores. Try coffee grounds and
discarded produce, for instance. Use chips from tree trimming
operations in the neighborhood to mulch your beds; tree companies
are usually happy to drop off chips for free or for a modest
fee. Better yet, use the wood as lumber for garden projects
such as benches, fences, etc. Broken concrete can be stained
with ferrous sulfate fertilizer to look like stone and then
stacked to make retaining walls or set in a bed of sand to
make stepping stones or a patio. Waste of many kinds from
construction projects can be turned into small structures
or garden art. One of the nicest planters I’ve ever seen
was a discarded brake drum from a large truck; these can be
obtained for very little money from a heavy-equipment mechanic
or a junkyard. There’s a mountain of interesting material
going right by your house every day on its way to the landfill.
Use your imagination and make use of some of it.
PROBLEMS NO
ONE HAS SOLVED YET: Until they learn to make pipe out
of soybeans (not so wild an idea as you might think), we’re
stuck with PVC pipe and all its drawbacks. For now, use drip
tubing where you can; it’s made from non-reactive polyethylene
that doesn’t contain dioxins and doesn’t require
solvents for assembly.
Many recycled
mulches are made from construction waste that may contain
lead and other contaminants, or from chipped trees that may
inoculate your soil with oak root fungus and other diseases.
Plus, some of these materials can be very flammable, especially
during hot weather. For now, I recommend using caution when
purchasing these materials and if there is any doubt, use
shredded redwood or fir bark instead.
As far as I know,
no one has come up with a durable, hard paving material that’s
also sustainable. For now, we’re stuck with concrete.
In fact, paving materials in general tend to be destructive
at their source. Use mulches in pathways where there is minimal
traffic and save the hard stuff for the front walk and other
public areas. If you must use concrete, specify a high-flyash
content mix that uses waste from coal-burning power plants,
and is much stronger and more durable than conventional concrete.
GO BEYOND SUSTAINABILITY: Unlike buildings, gardens are naturally solar-powered. They
are also capable of producing food for people. Plant an orchard
and a vegetable garden. Make use of the productivity of your
land to grow food instead of just flowers. It’s sure
to be superior in every respect to those supermarket tomatoes
that we all like to belittle. If you produce more than you
can eat or preserve, give the rest away to a homeless shelter
or rescue mission. Or to the neighbors; they like ripe tomatoes
and juicy plums, too.
Don’t forget
the wildlife. Provide shelter, nesting materials and food
for birds, mammals and other critters. Grow plants that attract
beneficial insects and they will reward you by patrolling
the garden for you.
It’s time
that gardens began to give back rather than take, to become
part of the solution to our problems rather than part of the
problem.
Other Articles by Owen E. Dell |
