tahiri wrote:

My Rosemary bush is dying and I don't know why. A few weeks back I realised
all the leaves at one side had died and I just cut out the bad bits and
hoped for the best because there were no clues. (When I say ''one side' I
suppose its the top really because it has always sprawled over to that side)
Examining the garden now the snow has cleared I see the rest of it has gone
very pale and hopeless looking.

Look at the branch nodes there is some white nasty fungal thing that
goes for them during cold damp UK winters. It seldomd kills the entire
plant but it can cause pretty severe die back down one side.

Don't rip it out until the end of the season it may regrow even if it
looks totally dead for a while in the meantime. UK winters kill them if
they get wet feet, wind rocking and/or aggressive frosts

Can they regrow from old wood? Suppose I cut it right back almost to the
trunk? I have always thought of Rosemary as a really tough plant and its
only about a dozen or so years old.
T.

It would be tough in a Mediterranean climate.

Regards,
Martin Brown