I agree, it doesn't look at all well, does it. I note the flower buds seem to be pink, and the head has a round look to it - H. paniculata usually has cone shaped flowerheads, so I'm interested in what shape the flower it had when you got it was...

First thing to do is to check all the stems and backs of leaves - you're looking for anything that shouldn't be there, but in particular, scale infestation. This should show as white fibrous bits or clusters on the backs of leaves or on the stems, almost anywhere on the plant. If you find anything, you will need to treat for it.

In the absence of that, find a spot for it in the garden, where you can be sure you will be able to give it a couple of gallons of water a week up until late autumn (unless we've having torrential, flooding rain), a fairly sheltered spot that isn't in full sun, (but some sun is fine) and not in a frost pocket. They like rich, fertile soil that is moisture retentive, so dig the area over and incorporate plenty of humus rich material, such as garden compost or composted animal manure from the garden centre, that kind of thing. Then plant your hydrangea, adding a handful or two or Growmore or Vitax to the planting hole, water in well.

At the moment, the plant looks like its been suffering either drought, not enough root room, preparing for winter, or been caught in some unusual cold after its started growing.

If it is H. paniculata and not macrophylla, they flower on new season's growth, so that means they can be cut down in autumn if you prefer to do that.

I have an old tub at the end of my path. Save all in house water that has been used for soap washing. Carry out in gallon containers, and keep the tub full. The oil from the soaps is good for plants.
Then when its dry drop my container plants into it for a good soak.
It stands in the shade. Costs nothing. Very handy.

There are a couple of red-leaved hydrangea. I'm fairly certain that when I bought 'Lady in Red' for my mother 7-8 years ago it had red leaves. Cost me a lot of money as a new breed and didn't thrive at all well. It had certainly shuffled off the mortal coil before my mother died.

Hi everyone,
Thanks so much for your thoughts and advice!

Bamboo, (such a comprehensive and thorough response, thank you!) I've checked and there's no sign of any scale, or anything else untoward...so that's a good start.
I think I'll plant it into the garden as you've suggested (and try and overcome my fear of overwatering!). It can't do any worse..! And I think you are right that it could have been mislabelled when I bought it - it was a handwritten label with a dubious spelling of 'paniculata', so there could have been some human error! Unfortunately, the flowers it had at the time were few and small, and my memory is so flaky that I can't recall whether they were more pointed or rounded in shape!

Diane...great tip about the water tub, thanks!

And Urbanite, parts of the stems are definitely red, as are the edges of some of the reasonably healthy-looking (albeit very small) leaves - so I did wonder if it was a red-leafed variety. Even so, it's definitely got some problems...

...I'll let you all know if I can manage to nurse it into health. Thanks again!
Georgie x

I looked up Urbanite's Hydrangea Lady in Red - yes there is one called that, and it does have red leaves when they first appear, fading to red edges and veining and then green later, so that might be this one. If it is, it's not H. paniculata, it's H. macrophylla, so pruning is the usual tidying up in spring after growth begins.

A word about watering - plants in pots generally can't be overwatered provided they have free drainage out the bottom (no outer tray holding the water in), and plants in the ground can't be overwatered because it flows away (unless there's flooding). It's always best to 'overwater' in the ground for new shrubs, they need extra help till they've put out their own water seeking roots, not to mention you want those roots to be at least 6 inches down, not waiting on the surface for you to come along with a pint of water occasionally. By that I mean water infrequently (once a week) but when you do water, give it a good soaking, a good couple of gallons.