The best way that I know to mask sound is to use running water. A waterfall or fountain or even several. I have one fountain with a solar pump (which obviously doesn't work at night), a waterfall and two other fountains that are plugged into outdoor receptacles. I also have some windchimes but many people don't like windchimes.

We have a gravel driveway and a business on the property which is why I want to mask noise.

Plants generally don’t provide much sound control. What kind of windows are in your house? If they’re single pane and as old as your house the best bang for your buck is going to be replacing them with double or triple pane windows. The sound attenuation from that will be noticeable.

Thanks for the ideas! I like the idea of running water, I just wonder how much it'll mask. And how much upkeep. We have dual pane windows already, and they do nothing.

I'd check out the windows. We have relatively new windows, as do one of our neighbors. Last summer there was a concert in the neighborhood that went late, and there was a big to-do about it. We were in bed reading and never even heard it, neither did the other neighbors with new windows. That is exactly as much as I know about it; but it makes me wonder if better windows wouldn't help.

They make triple thick pane windows for sound control. Might be worth your investment on the noisiest sides.

I think that flowering tree looks lovely spilling over the wall. If they are the smokers, it might block some of that, too.

You could build an arbor just in side your fence, tall enough to block the neighbors view and cover it with climbing plant, like a bougainvillea or wisteria that will fill in and give you privacy. And something pretty to look at.

Well, I'm not a pro, but I live in SoCal, so I know some things. If I lived where you do, I would crave privacy, and I would want to create a private oasis, or at least a front courtyard. Maybe that's just me! I would look at a fence to surround your front yard. Not only would it give you privacy, but maybe an extra layer of security. And then plant a hedge. I would find a sturdy, easy to grow (and shape) hedge, like maybe ligustrum texanum, which also has nice white flowers, and can be shaped.

You may also look into Italian cypress trees for your backyard, because they grow really tall, but you don't have to trim them regularly, and that would give you some privacy from the neighbor.

Here's the type of fence I would look into, for the long term.

"Camouflaging" noise with other sound is fairly common solution, but being someone who doesn't like noise, it doesn't work for me. The sound of water (or whatever else) that is loud enough to mask other sound, becomes just another annoyance contributing to a louder din. It doesn't help in trying to listen to conversation.

Plants are only good for controlling sound if you can install them in acres, but in a yard, they are more or less worthless. What works is solid, heavy walls, especially masonry. Solid (as in unperforated) wood is a second. though less effective solution. If you were in Pakistan, you could probably solve your problem. But here in the United States, there is virtually no urban place where the long arm of the law does not reach out to control what you are able to do with your property ... and tall perimeter walls, unless you are in a very high-end billionaire type environment, are generally prohibited. Usually, in the anti-tall-wall ordinances is included the phrase -- "exclusive of ornamentation" -- in regards to height restrictions ... meaning that you can add some type of decorative "edge" that extends above the height of the basic wall or fence. If you were to conceive of a decorative, solid panel type way of extending the height of your neighbor's backyard wall to the height of their garage eaves, but in your yard, that might be one way to overcome, or greatly minimize, their sound and smoke. Be careful if you push the limit like this though. If you go too far in a way that is offensive to the neighbor, they will fight you on it and try to get the city on their side, and may succeed. The best thing is to work out a plan that they are agreeable to from the start. (BTW, the part of the big bush of theirs that crosses over the property line, is yours to trim or allow to grow as you wish, which is a great thing about property lines.

There are probably variations when it comes to the sound-killing-effectiveness of double or triple pane windows. A regular window plus storm window would not be very good. I live 1/2 mile from a busy freeway, with direct line-of-sight and sound, and I literally hear nothing from inside my apartment. But when I open the patio doors, and the traffic is heavy, I am astounded by how incredibly loud it is. Other times, neighbors were blasting loud music and I was clueless about it until I opened the door. Even if your windows are not good at attenuating sound, there are some that are and you might look into upgrading them.

Where you are looking for privacy from your southern neighbors, might be the easiest problem to solve. Blocking the view at the top of the fence could be accomplished by using tree form plants that extend a few feet above the fence to a total height of only 10' or 12'. Surely, there is some large shrub that grows there that would be able to do this ... Pittosporum or something. It could be a large shrub form plant, but that would consume more yard space. But either way that works for you could do the job.

Road noise can be heard in the woods a great distance from the source. So even acres of trees aren't much good for noise abatement.

In my area freeway noise came to be dealt with by the erection of high concrete walls between the sources and affected neighborhoods. Even afterward the cars can still be heard on the other side, it's just that the sound now seems to come from the top of a high overhead wall instead of from near the ground.

Cigarette smoke is also quite penetrating, I have a cigarette smoker about 80 ft. behind me and when he is out there with a lit one in summer I can smell it down by my house - forget about me being anywhere in my back garden at these times, that much closer to where he sits or putters.

So, if the annoyances there are enough of a bother you may really just have to move away from them in order to get the circumstances you want. Someplace farther from urban noise, on a bigger lot - where smoking etc. neighbors cannot be right on top of you.

Very true on the water. It works well when there is traffic but I have a variable speed pump and I turn it down in the evenign if we are stiting outside. Otherwise hard to talk over the sound of the water!

And ditto on the cigarette smoke. Not a problem here, but really amazing how penetrating that acrid smell is.

Wow! All great replies! Thank you everybody! I've got some research and planning to do! We already have rose bushes surrounding the front yard in a hedge like manner, and they don't do much, so I'm not sure that anything further (within LA city laws regarding fencing) would work. So I'm thinking windows are our best bet for traffic noise. Regarding East neighbor, I hesitate to add anything to the masonry wall, but plantings might be in order. The neighbor who lived there before (miss him!) was always leery about anything that grew next to the wall however, because the roots would start making the masonry crack. Perhaps I can find the correct plant that won't interfere. South neighbor view blocking will probably be best with vines/arbor, as suggested. Or cyprus trees. However, there is no water that reaches back there behind the fence, so perhaps not. Thanks again all!

You could contact your county Master Gardener program. They often will send out someone who will do a consultation for things like this.

Master Gardeners aren't trained in design or this kind of thing. They are 'extending' the research of their land grant university. But it's a good suggestion for gardening questions. (I was a CA MG for 10 years, now Emeritus.)

I don't know about the Master Gardener program. I'll look into that.

Hoovb, I hadn't heard that about soil, that's interesting. Unlikely, of course, but interesting none the less. A quieter location is something we dream of for the future, but we were incredibly lucky to get this house when we did, right before the market shot way up. We're staying put for the foreseeable future as we'd never be able to afford now! In the meantime, triple pane windows with sound deadening are on the table. Thanks again!

Have you thought about attaching acoustic panels to the existing fence (like Fence Blokker, or the products found on acoustical surfaces inc?). I also live on a busy street - actually a rural highway, and am trying to come up with a noise dampening solution, too.