A line of young rhododendrons has been in place now for two years and
all have been doing well, then suddenly, last week, one of them gave up.
All its leaves suddenly drooped and started to turn dry and slightly
yellow.

Why? The ground is sufficiently acidic and all the others are fine.

I quickly did some online research and it seemed that maybe this
particularly rhody had got too wet in quite a lot of rain in the first
part of June. The drainpipe from the greenhouse roof washes onto the
ground a little uphill from this particular plant, but the ground is
raised about a metre above the adjacent road and so is well-drained.
Also, the rhodies on either side of the afflicted one haven't suffered
similarly and they show no signs of difficulty at all.

So I dug the afflicted one up. The ground was certainly wet, but not
sodden, and the top of the roots were level with the surrounding ground,
not covered by woodchips, and so had access to air. I noticed though
that on one side of the hole there were about twenty small white slug's
eggs, while on the other side there was one live slug. I was also
surprised that it didn't seem to me that the roots of the plant had
developed at all in the two years since the plant was put in.

Anyway, I dug the hole out an extra inch and put in an inch of pebbles,
to increase drainage beneath the roots, if that was the problem.

The plant has been back in situ for a week now but is showing no signs
of life.

Here's a picture of it, taken today.

http://i246.photobucket.com/albums/g...dyJuly2010.jpg

What should I do?

Wait? Cut it back? Give up and simply get another?

Thanks.

Eddy.