The septic tank should not be causing the problems unless you use a lot of chemical cleaners in the house. In fact, the shrubs, especially the holly, would relish the extra wetness from a failed soakaway.
Could this be another victim of the early cold winter. We have an unusual situation with our long established female holly. It was laden with red berries in October. In November we had heavy snow and it was very cold. When the snow melted at the end of November the berries were black and since then the blackened berries and most of the leaves have fallen off. Time will tell if the holly is dead or not.

Thank you bulbaholic..you have put my mind at rest as some of these trees i have grown from a twig, over many years. Only found the site today so perhaps we will speak again ..poppy11

Having a problem adding a photo to my member profile. must have missed the opportunity when signing up earlier.. Any clues...for a clueless??

Poppy, go to your home page by clicking on your name. Then to 'profile' and there you'll find 'amend profile'. You can add a photo for your avatar there. Good luck.