Fabulous Front Entrance :: how to plant a sound absorbing front garden….
In our Fabulous Front Entrance series,
we have looked at front doors, paint colours, lighting, door handles
and even Feng Shui….
But let's take a step further back from the front door,
to the front garden, and how you can plant it
to help absorb traffic noise.
Even if you live on a quiet street,
these ideas can help to create a sanctuary of quiet
in that very special part of the garden which lies between the front gate
and the front door.
And if you do live on a busy street, like me,
then using all of the techniques here can be very effective
in managing, or at least dulling, the sound of city life outside.
Sound waves : absorbing, reflecting, scattering….
When sound waves reach a surface,
the way they react will depend on the type of surface.
If the surface is smooth, rigid and hard, like concrete paving,
the sound waves will reflect back again,
so the sound level is not lowered,
it simply bounces around the garden.
But if the surface is textured, rough and flexible,
(like a mulch covered garden bed or a wavy leaf)
some of the energy from the sound waves is absorbed,
reducing the intensity of low frequency sound,
which is what we want.
Another way to reduce sound transmission is to scatter it,
which is what happens when sound waves
reach leaves and stems of dense vegetation.
Some of the energy is absorbed by the vibrations of the leaf,
while some of the high frequency waves are scattered in different directions,
which makes the sound less invasive to our hearing.
A well designed front garden should use a mixture of absorption and scattering
techniques to help reduce both the high and low frequency sounds.
Remember the old trick of placing a water feature by the front door?
It works, not because it absorbs sound
(ok, it does a little bit of that)
but because it is a decoy - we focus on the sound of the water
instead of the sound of the traffic.
Similarly, by using these 6 techniques to scatter the high frequency
and reduce the level of low frequency noise,
the sound becomes tolerable, rather than non-existent,
creating a garden which achieves a sense of quiet.
Because you want to absorb, rather than just deflect,
sound waves coming from the road,
the more textured surface area you can utilise,
the more effective the sound absorption will be.
(Just like a potato crisp with corrugations absorbs more fat
than a straight cut…it's a fun analogy, but it works!)
Imagine your garden is a 3 dimensional space,
composed of vertical and horizontal surfaces.
Each of those vertical and horizontal surfaces is an opportunity,
so fill every possible nook and cranny with plantings.
You can even create a "ceiling" by incorporating a timber pergola,
either attached to the house or freestanding
along the pathway.
Thickly planted with climbers, it increases the surface area
of your garden's sound-scaping potential.
In this garden, plants thickly cover the "floor" of the garden in a billowing froth of grasses,
but the walls have also been utilised, by growing self-clinging creepers on them.
Some plants, such as evergreen climbing fig,
are particularly effective for sound absorption,
although it's a plant which can do damage to the underlying structure,
so plant with caution and keep it in check.
Select plants which are evergreen to maximise the sound absorbing qualities
all year around if you can,
or at least use a backdrop of evergreen plantings.
The leaves themselves make a difference too.
Choose plants with thick, fleshy leaves rather than thin shiny ones.
Eg succulents, especially those with wavy leaves
have adapted to catch as much rainfall as possible
by increasing their surface area,
so they are a great choice for our sound reducing garden.
Smooth, or stiff leaves (e.g. pine needles) are not as valuable here,
as they will reflect the sound waves.
When sound waves hit a flexible leaf,
some of the energy is transferred into vibrations,
absorbing the sound in the process.
So the more flexible the leaf/twig/branch, the better it is at reducing sound.
Use hedges as a first line of defence,
paying special attention to corners where sound can sneak in through gaps.
An evergreen double hedge is particularly effective,
with staggered plantings reducing the possibility of openings.
Then fill in the spaces as thickly as possible,
creating dense plantings to suggest a woodland.
Avoid hard surfaces, such as concrete, metal, bitumen or even brick paving
as they deflect sound waves,
making it bounce around the front garden.
Instead, incorporate more textured materials, such as timber sleepers
for pathways and edges, tumbled rocks and dolomite gravel,
and mulch every garden bed with organic matter (straw, bark, leaves)
because it is a brilliant product for absorbing sound.
A timber fence, especially if constructed with closely spaced palings,
is useful in absorbing quite a high level of sound.
With apologies to Le Corbusier, less is not more in this case.
The more plantings, the merrier.
Lots of little clusters are much more effective than specimen plantings,
because we are trying to create thickets.
Group the plantings together, placing 3 or 5 plants of the same variety
very close together in families,
then place a different type of plant grouping close by.
Choosing plants with rough bark is a terrific way to introduce more texture
into the garden, which as we have seen, absorbs high density sound waves.
One of my favourite plants in any garden is the very ancient tree fern,
and with its scaly rough barked trunk and huge crinkly leaves,
its a wonder plant for sound absorbtion.
(I am about to plant about a dozen in my own front garden!)
Other good choices include the cork tree, eucalyptus such as iron bark,
and melaleuca or paper bark. Any interesting textured bark will be beneficial,
as well as providing interest in the garden from a visual perspective.
Use a variety of shapes to maximise the heights at which the sound waves
are travelling : to "catch" them as they pass, so to speak.
Tall trees, short bushy shrubs, dense ground covers or long grasses...
…the more variety the better the catchment.
So if you live on a busy street,
try incorporating at least some of these ideas to create a sound barrier,
and at the very least,
it will create a green sanctuary which is an important part of creating
a Fabulous Front Entrance.