How do I block traffic noise in my back yard?

Google “garden Extension Service, along with your town and zip code.

I suggest this because we don’t know your area nor what plants would work best. You want shallow, fast growing plants that probably don’t grow above 8 foot.

Virtually every county in this country as an agricultural or Master Gardeners extension service which offers free advice on what grows best in your specific area - soil and weather conditions, etc.

Every expert loves being asked for advice. Best of luck.

Some good basic info here: https://www.gardeningknowhow.com/special/spaces/noise-reduction-plants.htm

Velia what about a noise barrier? Normal garden hedging will offer you very little or no acoustic protection from noise, There are plenty of "natural' wooden paneled fences on the market which because of the offset nature in their design, offer excellent noise reduction properties. You see them all over the place in residential high noise areas.

Velia, I would buy a couple of solid fence sections and plant some tall shrubs in between. The fence sections are your best sound barrier and the shrubs will soften the look and give a softer, more natural barrier. Arborvitae is the shrub I would look for if it grows in your region. It grows tall and narrow and is an evergreen, so you would have your sound barrier year round.

Hello, well I have “skip laurel” on one side of my house. The good and the bad. The good - it works wonderfully for sound and it looks nice and they grow fast, the price depends on the height and which laurel you go with. . The only bad - you have to trim them every year if you want them to look nice. We just shave them straight up like a wall and straight across the top. When you look for shrubs or trees just look for those that have growth from the ground up and that will grow to the. Height you want and can manage. If you don’t trim them, they can look odd but I don’t think it will hurt the plants. You can also choose junipers or hollies. I am unsure where you live so you may need to keep that in mind. I am here in Pennsylvania. Good luck with your project.

a nice laurel hedge grows fast, will grow tall and thick to deaden sound. If you know someone who has a laurel hedge you can take and root clippings in pots till they are about a year old. Laurel also stays green all year here in Oregon and the occassional snow storms doesn't hurt them either. You do need to prune regularly to keep them in shape.

https://www.google.com/search?q=pictures+of+a+laurel+hedge&client=opera&hs=mR4&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwiX-cyhh9TcAhWrGTQIHQ7CBCcQsAR6BAgFEAE&biw=1473&bih=675