Restoring overwatered rosemary

Question

I have several rosemary bushes in the backyard; I live in San Francisco and rosemary thrives here.

However, the landlord overwatered one of the bushes for several months. It's now got some kind of fungus or root-rot which causes it to look unhealthy and the leaves on some branches to turn yellow. Since then, I've removed the soaker hose he put there, and have been letting it dry out. It doesn't seem to be getting better though.

My question is: is there a way I can rescue this rosemary bush? Should I expect it to recover with mostly dry soil and infrequent watering? Or is it doomed at this point and I should rip it out and plant another one?

Answer 1

I'm actually going to answer my own question, because it turned out that the answer above was not correct. I got some offline advice, and what I did instead was:

1. Aggressively prune back the rosemary, cutting off all the yellowed branches.
2. Water it infrequently for the next month, allowing it to dry out between waterings.

The rosemary is now restored and growing again.

Answer 2

If the plant really does have Foot and Root rot, best remove it as soon as possible. There is no effective treatment available.

Update:
Ok, then I'd get it out as soon as possible. Because this is a shrub or a woody based plant, even though Rosemary isn't particularly prone, when they get root rot, its usually caused by phytophthera, so best removed asap, together with some of the soil from round the roots.