Cypress Browning

Hi there.

I'm new to this forum, so I'll quickly introduce myself. My name's Steve and I'm the proud owner of a large garden on the edge of the Fens in Lincolnshire. Although I'm not new to casual gardening, it's an interest that I've had to develop very quickly to keep our new garden as nice as it was when we moved in. I'm also doing a bit of landscaping in the part that has not been touched.

I'm going to start with a question. I know that conifer browning is a common issue and that there is a lot of information on the internet about wind damage/root and needle disease etc, but all the descriptions are about browning of the branch tips and not the problem that I appear to be having.

I have quite a large number of 10 year old yellow conifers (They may be cypress as they give the usual lemon scent, but I'm not totally sure). I don't think that they've ever been pruned. When we moved into the property, they were healthy and yellow all over. Now it appears that it's browning from the inside out. I know that these conifers die in the middle and that it's only the outside that has the living growth, so I'm wondering if it is the fact that there is no new growth to mask this. There are a few photos and more info on my blog.

http://mallardlodge.blogspot.com/2009/07/yellow-conifer.html

These photos were taken last year and they are significantly worse this year.

What should I do? It would be a shame to have to dig them up.

Another couple of questions: Is it true that these conifers can get too old and past their best? and Should I have to feed them regularly.

Thanks

Steve