A Guide to Privacy Landscape Design in San Diego: Blocking Traffic & Other Noise

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  • Post last modified:February 8, 2024
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Landscape plants, fencing and block walls are all good ideas for lowering the sound of traffic on a busy street or trying to keep the privacy of a small home.

Many neighborhoods are close to streets or noise because of the cost involved for the property. Sometimes, just making sure that certain rules are applied can help tremendously with creating a safe space or a calmed back yard where it once was loud and obnoxious.

Sound is very interesting. Sometimes traffic noise can be dispersed with barriers, other times it can be channeled away with grade changes or it can be masked with the sounds of water or wind movement.

What is unique to sound is that it is line of sight. Another words, it is most powerful when it is generated toward an object or property that has no barrier between the sound and the home being affected.

Plantings can disperse some of the sound generated by an external source but, as with all barriers, the plants must be tall enough to stop the sound from reaching the person or property that is under attack.

Layering is another good solution to noise pollution. If a hedge does not stop the sound being generated by vehicles or something else, planting another row or two of plants to create a double or triple screen from the noisemaker can be a cheaper and better solution.

Installing a block wall that is tall enough to stop the sound and then planting some materials that will grow taller than the block wall is always a good solution. Building the wall on a slope higher than the house also makes for a good barrier because the sound will then go over the home in question and reduce the line-of-sight noise that has become a problem.

Typically, a wall, glass or a physical barrier will not stop all the noise. Most often it requires a mixture of things applied in tandem to do so. Let’s say you have a block wall, several hedges planted and still the noise is unacceptable. You can then mask or make the noise less noticeable by introducing a water feature, a water fall, or something that continually makes a sound that competes against the noise maker.

A physical or moving source of sound masking is usually a good choice for this technique. Being able to see the movement of water or a waterwheel in action draws attention to the sound being produced and tricks the mind into listening to this source of sound and not the unwanted noise. I like this technique because it gives the observer control over the sounds he wishes to hear, and not the sound being generated by the unwanted source.

Placing a water feature near the back yard of a house or near the backyard patio will often do the trick of masking or hiding the offensive sound because of it’s proximity. Sometimes traffic sounds are less noticeable because some vehicles closest to the outside wall or hedges are going down a hill and the engines have less work to do. Going up the hill instead of going down the road also makes a road louder and more difficult to hide but if you are lucky, the location of the noise and what they are doing is further away from your structure and is less noticeable.

Another great thing about sound reduction is that vibration from the noise maker can be absorbed or reflected away from the receiver before it reaches him. Case in point, thick bushes, high density leaves and good tight wood structure are definite positives when choosing the right type of plants to solve this problem. Some of the most desirable plants for noise reduction include: Texas Privet, Oleander, Baby’s Breath, Podocarpus Gracilor, Photinia or Eugenia. Not all of these are non-toxic like the Oleander but they all grow tall enough to help block or absorb noise and another layer of plants can be added artistically to them to help stop the problem before it reaches you.

Another thing to be aware of is that noise requires a physical substrate in order for it to be carried.

There is no sound in space, only a vacuum.

Noise reflects off of air and can go around or over a barrier to some degree. This is why several different solutions to the vexing problem of sound pollution must be applied to get a tolerable solution. I have seen many homes with freeway noise. The best solution is to create a barrier far from the home or person receiving the ruckus.
Large trees don’t do much for sound reduction because they usually have a single trunk that doesn’t absorb or stop the vibration at a lower level. In some cases, the canopy up above can reflect the sound down to the homeowner and increase not decrease the sound pollution.

Remember, noise is line of sight. The straighter it heads to you the louder it will be. Sound emanating up into the sky will still be audible but on a much lower scale.
Creating a physical barrier far away from the home owner made of block or glass is a good solution but the cost for such a structure is prohibitive. The sound can also go around this structure. The best solution is to add plants to this barrier in two or three rows and to wrap them around the backyard to prevent additional noise from seeping into the living space. Also, designing the landscape with this thought in mind, create an attractive water feature near the living space you wish to help mask or compete with the noise coming from the freeway or some other source that you have no control over. You will never be able to stop the noise completely using this technique but your pocketbook will thank you in the end.

Tall palms or thin structured plants with great height will not help with the noise reduction and can reflect the sound around the property making it more difficult to reduce by throwing it in different directions. Ultimately this can confuse the homeowner and over time, the small trees that he planted to help solve the problem are now making it worse.
Another thing about traffic noise that is interesting is that wind coming from the direction of the house towards the street or highway can mitigate or help with the reduction of sound and noise.

The wind can actually blow away the vibration much like water can carry away dye or small particles of dust in many circumstances form the main body of water.
Unfortunately, the opposite is also true with noise. If the wind is coming from another direction across the highway to the housing tract, it can carry up to twice the sound level that it did when the wind blew in from the other direction.

This is why it is so important to look at the new domicile or home you are going to purchase at several times during the day and on the weekends. Typically near the beach, the wind will be offshore in the morning and calm during the night. It will then blow hard on shore during the day due to the furnace or heater of the sun. Late afternoon is usually the time of day where a switch in the wind direction occurs and depending on the location of your new domicile, it can help or hinder the noise you are receiving from the highway. Time of day also affects the noise level of some homes because the freeway can be very busy in the mornings and evenings when most people are going to or coming home from work. This can complicate your choices somewhat in choosing a house but in the end the purchase of a new home is usually subjective. It all comes down to what the home new homeowner can put up with for the price of the new place and the noise he is accepting. Sometimes, after careful observation a new homeowner will decide that the new price of the home is sufficient for what he is paying for.

By planting the proper plants around the property lines, by creating an impenetrable barrier with a block wall and by designing the space with the thought of water masking, a new owner can get 3-5 years of growth from his plants, reduce the overall impact of sound upon his backyard and make great gains on his investment.

Remember, nothing is perfect. Some investments are much better than others and you cannot always control what is happening outside of your property lines.

Be careful about the choices that you make and if you are not entirely sure about what can be done to mitigate the sound that seems to be coming into your yard, have a professional take a look at the home you intend to buy.

He will be able to tell you quickly if the choice is right for you.