I'm not sure how much noise you will reduce by using plants to screen. Have you thought about plants and a fence? The laurel hedge would fill the area in relatively quickly. I have two at my house and they grow like crazy... bordering on invasive. Sometimes I wake up in a panic thinking the laurel has grown into the house.

Laurel is probably going to need heavy irrigation in your climate to maintain healthy green color and a full shape. And I'm not usually one to be pessimistic about hardiness, but just how much cold can those things take? I don't recall seeing them in Pullman, except for the lower growing 'Otto Luyken'. It would be a shame to have a cold winter come along and see massive damage on your hedge.

Personally I would go with some larger growing, dense evergreen trees - Calocedrus decurrens comes to mind as an excellent choice (unless it's going to create a problem with allergies - I'm not sure). I think whatever you do, you may be disappointed with the actual ability of plantings to reduce noise, as people usually are.

Thanks very much for this input! We have looked at stucco and other types of walls, including fencing with a hedge behind. We were hoping to get by with one or the other, but are now leaning toward both. Since I wrote that note, the landscaper has decided laurel wouldn't be a good choice after all due to the snowload. We did spend a little time researching laurel, and it sounded a little scary as if it could take over. Luckily, we own a chain saw.... Otto Luyken was the variety all right. He's now recommending Simplicity rose bushes, but I think we'll steer clear of those too. We're leaning toward a mix of trees and bushes to come up with a visual barrier rather than a sound barrier.....Excited to put up something, but don't want to plant a disaster-in-waiting, like 200 feet of crushed or dried up hedge. Since we have some red cedar already, incense cedar would be a good match, too. Thanks again, appreciate the suggestions and warnings.

What about bamboo for noise? I think it's very effective, judging by the experience if some friends who planted it when they lived on a noisy street--

I wouldn't worry too much about laurel taking over where you are. It's more of a western Washington phenomenon. 'Otto Luyken' should do well for you but it doesn't really grow tall enough to be much of a screen.

I like the idea of having a mixed planting with a variety of different plants - to me that is more visually appealing anyways.

The bamboo idea would work pretty well only if you can give it a lot of water all summer. You can control its spread by not watering outside the area you want it to grow. I would stick with the very hardiest species such as Phyllostachys aureosulcata and its varieties, P. bissetii, and P. nuda - they should be successful overall but expect some winter damage. Fargesia nitida and F. murieliae are also very cold hardy and don't spread, but they will require a mostly shaded position where you are.