The first thing is look closely at the soil these are growing in. What is the pH of that soil? How much orgainc matter is in that soil? How well does that soil drain? How well does that soil retain moisture? What kind of life do you see in that soil?
Insect pests and plant disease mostly affect plants that are not strong and healthy, growing in soils that are good and healthy and that is why it is a good idea to start with the soil.

Thanks for the suggestion. I'll go buy a kit and take a sample.

I'm confused though. Considering the plant on the right is doing great and the others are having problems, I don't understand how it could be the soil. They are all the same exact plant and planted in the same soil. Why would the soil conditions only effect the bushes on the right?

Also, I have no idea what kind of bush it is so I don't even know what soil conditions is prefers. :(

I bet the problem arose from the original plant. My guess is the roots of the plant on the left were root bound in the pot. You can try root rejuvenation by cutting the roots near the original potted plant. If you want to try this, post back.

Derek, they are laurels. It looks like you have some minor insect damage (may be root weevil), possibly some fungal leaf spot (not uncommon on laurel) but for one plant in a group to look remarkably healthier than the others I would guess something environmental. Planted rootbound, different exposure to freezing winds - are you on the E side then if you show yourself as Z5? Do you have a sprinkling system that is inadequate for that curve of the bed where they could have gone into winter drought stressed? It looks like you have a stone mulch there, and while I can't see it clearly, larger rock/rocks at the base of the failing plants? I can see something there too that almost looks like plywood beneath, but again, I can't see it well...

petzold: Thanks for the suggestion, but that sounds a little too involved for a weekend warrior like me. :)

morz8. First, thanks so much for identifying the bush. Also I must apologize; as soon as I read your post I realized my zone must be incorrect in my profile. I am in Tacoma Washington which makes me Zone 8.

I can't image there not being room for root growth as they could branch out all the way into the grass. I do have a sprinkler system but from what I've seen it covers all the bushes fairly evenly. I'll set out some bowls to test water distribution just to make sure.

The larger rocks at the base of the laurels are about 2 inches in diameter. I removed all the weeds and barkdust in that area last summer and replaced it with a weed barrier and rocks for easier upkeep. What looks like plywood is a red brick edging around a utility service grate behind the planting bed. The bushes with red lava rock are actually my neighboors. Here's a zoomed image to see better. Thanks again for your help and suggestions!

{{gwi:1152220}}

Derek, 'rootbound' shrub refers to the original installation - you didn't know what they were so I assume you didn't plant them. Often container grown plants will grow with the roots encircling the pot shape, if they aren't loosened or even cut to open them up, the roots don't establish into the surrounding soil, eventually the shrub exhausts all nutrients that were available to it and dies. Can be problematic with rhododendrons, I haven't planted laurel myself. I'm not growing it either but I think I will link your question on the Northwest Gardening forum where someone in your immediate area will likely see your photos.

It is possible the yellowing ones are getting more water and not draining well. Portuguese Laurels require good drainage. If the raised bed was made with ordinary garden soil and not amended it may drain just as slowly as local clay soils do.

It is also possible that those are getting less water or that their rootballs weren't properly loosened when planted as already suggested.

Prunus lusitanica is usually pretty darn easy and they've spread to naturalized areas and might be added to the noxious weed list if they aren't already.

I see no Portugal laurels in these pictures, these are English laurels. Both species pop up frequently from seed in gardens, parks and undeveloped land in and around local communities.

The holes would be Prunus shothole. The yellowing would be too wet, or nitrogen deficiency or etc. as suggested above.

As the root goes, so goes the top.

These particular plants are a dwarf form of English laurel. 'Otto Luyken' is very common. Chlorosis is common with these plants, often from poor drainage causing root rot, or sometimes iron deficiency from improper soil pH. They like a slightly acid pH, which is the general pH of soil around here, but who knows what it is in a raised bed like you've got them in. The soil is probably hauled in for one thing, and masonry can change the soil pH.

Soil can vary tremendously from one spot to another just a foot away. These are not the exact same bush, you have a number of individuals of the same kind; and they are not all in the same soil, each one is in its own spot, which can have very different soil conditions.

They look like they've been in for a long time, not recently planted. So they could be rootbound, but it could also be something like winter damage, or root rot from January's flooding, or a particularly good year for root weevils chewing on the roots could cause the yellowing too.

See how wet the soil is where the roots are, and what the pH is. The soil should be starting to dry out by now. You do not want it to be wet all the time. If the soil is moist but not wet, and doesn't smell of rotting eggs, then try giving them some liquid fertilizer with chelated micronutrients. A shot of Miracid would be just the thing. See if that greens them up. If so then you know it's a nutrient deficiency. You shouldn't need to feed them very often though, maybe once a year.

That planter you have them in does look rather crowded. There's as much root below ground as branches above. And you're watering them already?? seems early to me, you could be keeping them too wet. I haven't watered anything in my garden yet, just the smaller pots.

Zone 5 is not incorrect for Tacoma, just it's zone 5 in Sunset Magazine's system. Zone 8 for Tacoma is the USDA system. Either one is correct, just you should specify which one you're using! 'cause zone 5 WA in USDA is Spokane.

reg pnw7,

You nailed it on the some of the soil based problems with this cultivar...but not "Otto Luyken", "Schipk." Laurel (Skip Laurel)...the west coast form to be exact (head nod to the east coasters that know the older, better east coast form).

Schmoo

Wow! Thanks to everybody for their suggestions and advice. It's greatly appreciated!!