I live on a busy street. What kinds of plants or walls will help?

December 23, 2016 10:49 PM

I live on a busy suburban thoroughfare in the pacific southest of the US (planting zone 10a). I'm wondering what if any plants or walls I could erect to reduce the noise? I had imagined a 6' tall stucco wall or perhaps a jade plant hedge (I know someone with excess jade plants, so I could get an instant 4' tall hedge at little cost). What would work best?
posted by arnicae to Home & Garden (14 answers total)

Best answer: There are fast growing species of Podocarpus that you could plant now and shape into a wall. I like them, not the thickest sound barrier, but so so attractive. I think some sort of box hedge is a thing here in LA? Is that the name for them? Those big walls of bushes??

If I were you, I would go with a tall fast growing bamboo - ask a professional if you want running or clumping type. Dead sexy. Will do the job.

Ginkgo trees eat pollution, but I don't think they grow fast or form at all into a hedge.
posted by jbenben at 11:06 PM on December 23, 2016 [1 favorite]

Check with the city first. My mom wanted to do this and would have had to have a traffic study done to prove she wasn't blocking sight lines. Or, stick to plants that can be cut or removed if needed.
posted by jrobin276 at 11:10 PM on December 23, 2016

How much space do you have to work with? I personally think that an attractive solution is a wall of landscaped plantings that people who use the sidewalk can appreciate, and then a solid (eg adobe) wall behind that.
posted by aniola at 11:32 PM on December 23, 2016

This yard on my local busy road is a fancy/manicured version of what I'm talking about, maybe minus the grass.

My point in showing this one in particular is that if your yard is already amenable to something like this (drainage?), soil is probably a pretty great noise barrier, too.

Behind that wall, the ground is a little lower. I think they built up the soil in front of the wall so that there's a gently upward sloping hill until you get to the wall, and then on the other side of the wall it's lower and there's a secret peaceful patio-like area.
posted by aniola at 11:47 PM on December 23, 2016

Less fancy versions of the above still look pretty great, though.
posted by aniola at 11:49 PM on December 23, 2016

This Old House has a nice piece on noise reduction. Apparently walls are more effective than hedges, but plantings can help (perhaps more psychologically than in other ways). The Federal Highway Administration offers four physical techniques to reduce noise impacts but doesn't think plantings are that useful. The Georgia Forestry Commission (PDF) disagrees and suggests green buffers for noise reduction. Good luck!
posted by Bella Donna at 7:08 AM on December 24, 2016 [3 favorites]

Be exceedingly careful with bamboo. It is invasive. We will be paying annually to combat our neighbour's for the rest of our lives.
posted by DarlingBri at 8:18 AM on December 24, 2016 [8 favorites]

Search terms include absorbtive and reflective. I read an article a while back that talked about seven different kinds of sound barriers and the properties of each of them, and I can't find it now. Those search terms should get you started down the rabbit hole of figuring out the properties of your assorted options.
posted by aniola at 9:49 AM on December 24, 2016

Pacific southeast?
posted by humboldt32 at 9:57 AM on December 24, 2016 [1 favorite]

You might try dual-glazed windows on the side of the house facing the noise source, if you don't already have them. Compared to single-glazed windows, they are enormously effective at blocking noise.

You might consider installing them on sides of your house if you get reflected noise from your neighbors' houses.

Of course, this only helps with noise inside the house. The yard will be as noisy as ever with dual-glazed windows.
posted by the Real Dan at 10:04 AM on December 24, 2016

My understanding is that vegetation doesn't do much for sound. The wall would work better.
posted by cnc at 11:58 AM on December 24, 2016 [1 favorite]

When we were looking at houses to buy, one of them was next to a somewhat busy road. The driveway was quite noisy, but it was significantly quieter on the side porch that was screened from the road by a thicket of bamboo.

There was a 4-5 foot wall also, which did block the road visually from the driveway, but as I said it was still pretty noisy, probably due to reflections. So I suggest both a wall and a dense hedge of some sort if you want to see significant improvement.

The engine noise is still going to carry through, but you will be able to cut down on the rolling noise of car tires, which is itself quite loud at speed and in some ways more annoying to me.
posted by wierdo at 3:19 PM on December 24, 2016

Bamboo won't do a thing to dampen sound. I have a bamboo hedge on two sides of the yard and the only thing it does is keep the street out of sight and attempt to take over the whole yard.

cnc is so right about the double glazed windows being effective at sound reduction inside the house.
posted by a humble nudibranch at 3:19 PM on December 24, 2016 [1 favorite]

Best answer: A masonry wall will be best but NOT with a straight top - or a smooth face. I'm not an acoustic designer ("just a %^&king gardener": according to a potential client who I decided not to work for) but AFAIK sound tracks over even-topped structures... For instance I've designed a earth bund with randomly-placed concrete chunks along the top like a dinosaur to dissipate up noise from a tractor dealership.

Essentially all road noise sources have a noise signature from different road materials, surrounding buildings, vehicle mix etc so to be effective solutions need tailoring to the site; it may be worth looking for an environmental designer who really understand plants and road noise and is willing to think outside the box.

Also look for Fine Home building, 2002, issue 145 - A quiet house on a noisy street. About a house at a very busy intersection in Albuquerque. The architect designed a block wall where each block was placed as randomly as possible, and the top was all jumbled. This was complimented by a plant selection of hard leaved, spiky plants and rough ground (always use evergreen plants). For some sites this is exactly the approach I would take but with plants-only solutions acoustic theory has moved on a bit so consider...

Vegetation can work for sound but the approach is (currently) very technical but google this "toolbox from the EC FP7 hosanna" and save the 2nd item down (if it doesn't open PM me and I'll send it) - it's technical but pictures are very useful.
posted by unearthed at 8:54 PM on December 26, 2016 [1 favorite]