Dying Skimmia - pls help

We have a 6-yr old skimmia on the shady, north side of our house in a protected area (We live in zone 7a not far from the ocean). Within 2-3 months this past summer, parts of the foiliage turned pale green, dried up, and died. We cut off those branches and I have attached a photo of the remainder of our bush.

We took a branch to our local garden center and they detected nothing wrong -- no bugs, no scale. They took a cross-section of the stalk and saw nothing unusual.

10 yrs ago we had another mature skimmia of the same variety on the same side of the house but in a different spot which also died in this manner. After the first signs of illness, we transplanted it to another shady spot on the property -- less protected -- but the plant died back slowly over the course of several years anyway.

We have never sprayed, wrapped in burlap, or done anything for these skimmias other than water by hand (we do not have an irrigation system). We may have fertilized, but we cannot remember. Adjacent bushes doing fine are: euonymus, leucothoe, and english laurel.

Could anyone help us with our skimmia dilemma? We are not sure what kind of care these bushes need and we have no idea what causes them to die back. We love them and would like to grow them successfully.

Thanks!

Here is photo of the whole bush (after having cut the dead out of the left side).

I looked online and found you some information.

Carol

Skimmia is an ericaceous shrub. It requires acid soil or it will get chlorosis and go yellow. Even if you have acid soil, the soil near your foundation might be alkalina and cause a problem. Look for telltale yellow leaves with green veins.


Question from Douglas French: Last year I planted a straight row of seven Skimmia japonica five feet apart. This year plants one, three, five and seven are growing new leaf and look quite healthy; plants two, four and six have yellow dropping leaves, and they look as if they're about to die, why? They were identical plants from the same nursery, and planted in precisely the same way.
Pippa: Very depressing. If you give it six months they'll all look terrible. I don't know what's causing it. Skimmias either love it or hate it in my experience. If you find the right spot they're beautiful, but they hate every other spot in your garden. They go yellow if the soil is too wet, or if it's too dry. They are prone to phytophthora, which is a soil-borne infection, and it's unlikely that it would take out every other plant in the row, but it has got to start somewhere. So concentrate on keeping the plants in good condition. You need to keep the water levels even so they don't dry out. I'm not saying skimmias have to have a really wet site at all, but if it is too dry you will get dreadful defoliation, and ultimately a lot of those bleached shoots will die back.


There are both male and female varieties of Skimmia, you need both if you want berries, but if you are short of space there are hermaphrodite varieties available. The male plant gives off a lovely scent in early spring. They need iron and magnesium to maintain the intense green colour.

They like a light acid soil, spread peat around the plant to maintain an acid state. No pruning is usually needed; the plant tends to maintain a tight form of growth. Only major pest is the vine weevil, which attacks the roots, treatments are available.