Are your shrubs boxwood? http://extension.umd.edu/learn/ipm-series-boxwood-hg52   Boxwood has opposite leaves, ie. the leaves are opposite each other on the stem. http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=376  It looks like the leaves are alternate on the stem, in which case, it would probably be a Japanese holly. Make sure there is no mulch touching the stems of the shrub. What you have looks like something that you cannot spray and thereby fix. Scratch the bark and see if there is green under the bark of the affected portions. If there is no green, get those portions cut out. It could be winter damage. Old Japanese hollies sometimes lose old stems. When the affected branches are cut out, they may look a bit scraggly for a while, but they usually bounce back, unless voles are chewing on them.  vw

Thanks for the information. You are correct - it is not the boxwood that w always thought we had!  It fits everything  about Japanese Holly.

Yesterday I finished one section of the bushes, pulling out mulch and pine needles that had blown in from the neighbor again, scraping the suspect branches for "green" and removing the dead branches.  Usually a tug made the branches snap off. 
1) The interior of the dead branches is almost white and very dry. Does that have any particular significance?
2) When the branches snap off so easily, do we need to seal the exposed spot with anything?  Does the exposed part need to be finished off better with a cut/trim with a saw? (Very hard to do that considering the tangled branch structure and lack of easy accessibility.......)


Thanks for your help!

You do not have to seal any of the pruning cuts, they will heal naturally Being that these plants are over 25 years old,a regenerative pruning  may be helpful. With this type of pruning the plant is severely to about a foot of the preferred height.. The other consideration, is to replace them. Otto Luykens cherry laurel is a lot easier to maintain and should do well as a foundation plant.

ro

Hello, We are going to try the mulch/leaf pulling form the base and lower branches and also the  pruning out of all dead wood we can find.

1) IF we go to the regenerative pruning idea, what time of year is best to do that?

2) Is there anything like Hollytone or an booster we can offer to these plants at this time?

3) I feel no soft ground at all , but should we put anything there to kill voles if they could possibly be part of the problem??  Thanks.

Major pruning should be performed in the early spring. You can do it now. If your hollies are mulched,  the breakdown of organic mulches contributes nutrients.
Where growth is lagging, top-dress the shrub beds with well-decomposed compost.
Voles - are a type of mouse that feeds on roots of trees, shrubs, and herbaceous plants. Look for silver dollar sized holes in the mulch and around the base of the plants and trap with mouse traps if need be. See our website for more information
http://extension.umd.edu/hgic/voles
Make sure the soil drains well and there are no downspouts dumping water into the beds. Poorly drained soils contribute to root rots.
mh

We have tried all of the suggestions. The mulch is pulled away from the stems of the bushes and even the overhanging parts of the bushes. Today we noticed these cracks in the ground. It looks like cracked mud and the entire area is rather hard. There is no soft feeling of underground tunnels, etc

Interestingly, the worst bush has almost all the cracks beneath it. 

I was attributing the cracks to the absence of the mulch which always helps hold the moisture. 

The soil cracking is due to a lack of moisture,this area may need to be irrigated on a weekly basis. The addition of mulch will help preserve any soil moisture. As the mulch decomposes, it will add organic matter to the soil, this will also help preserve moisture.


ro