One of my favourites is East Ruston Vicarage Garden in Norfolk. Lots of different 'garden rooms', unusual plants, a wildflower meadow and a dry desert garden.

I would recommend the Royal Botanic Garden Edinburgh [http://www.rbge.org.uk]
Branklyn Garden in Perth [http://www.nts.org.uk/Property/Branklyn-Garden/]
Cluny House Gardens in Perthshire [http://www.clunyhousegardens.com]
and Inverewe Gardens [http://www.nts.org.uk/Property/Inverewe-Garden-Estate/]

I could suggest many, many more...

Is it just England that you are visiting? For me the must not miss are:
Wisley
Heligan
Sissinghurst

Kew is pleasant and encyclopaedic but I prefer the Chelsea Physic garden.

Heligan - and there are lots of other gardening places around to justify the long tedious journey to Cornwall.

Northern England:
Alnwick

Scotland:
Botanic Gardens Edinburgh
Logan (sub tropical garden in Galloway)

Am sure others will give you a much larger list!

Klahanie I suspect we could give you a list of so many gardens you needed to be here for a month or more :-)

Thank you all for your reply. I know that UK has many wonderful Gardens and I will be putting together a list generated from my search on the internet. I just did not want to miss the most beautiful and interesting ones.
Thanks again, I will look at the your suggestions.

My question perhaps should be "If you had to choose the 10 most interesting gardens which ones it would be?"

It also depends what time of year you are going since some gardens are famous for their - rhododendrons - roses - bluebells in the spring - etc. and not necessarily as spectacular at other seasons...

One of my own very favourites was Christopher Lloyd's idiosyncratic gardens at Great Dixter in East Sussex - I remember a magical birthday outing there in a hot July, some years ago - but I don't know how it has fared under his successors...

We are members of N Trust and Historic Houses and over the years have visited lots of places but would list these as my favourites -

Stourhead: end May June and also in Autumn
Leonardslee Gardens - Fabulous rhododendrons and lovely walk
Exbury Gardens & Cockington Village - rhodos and picturesque place and little train,horse & carriage rides.
Powis Castle - stunning borders - and views!
Sheffield Park Gardens - more manicured but great walks and lovely specimen trees, well worth it.
Hidcote Gardens: Individual "rooms". Also very close to Kiftsgate Gdns, Snowshill, and the magical Sezincote
Ifford Gardens: Hillside Peto gardens near Bath - very unusual
Malmesbury Abbey Gardens - home to the Naked Gardeners and fab gardens
And of course Sissinghurst, the Royal Hort.Gardens at Wisley, Rosemoor, Harlow Carr etc.
Hope this helps

Thanks Monjardin and Tetrarch
I will google all the places you mentioned. I am working on my DH.....to visit next summer.

I would recommend Thornton Hall gardens, it is only open about 7 times in the year from May/July. I went last year and it is amazing. Here is the web site for it.

http://www.thorntonhallgardens.co.uk/

Also Harlow Carr is well worth visiting as is Gresgarth Hall nr Lancaster.

Hope you manage to make it over here next year.

Thank you for the link and the suggestion Susie.

Fully agree with Susie ..... In all my years of visiting gardens, Gresgarth House is my favourite. You are then near the Lake District which has some fabulous scenery and hotels.

Thanks Alan. It is always good to have several cheers for the same place. I took a note.

Hi Klahanie, please be aware... I think Gresgarth is ONLY OPEN on Sundays, .......... and once a month.

Sunday 11th May, Sunday 8th June, Sunday 13th July Sunday 10th August, Sunday 14th September.

Another possibililty would be the RHS Show at Tatton Park (depending on your visit dates of course). This is 20 minutes drive from Manchester Airport. We go with friends every couple of years ... its a good day out.

RHS Flower Show Tatton Park, 23-27 July 2014
(Tickets £24 each, I think).

http://www.rhs.org.uk/Shows-Events/RHS-Show-Tatton-Park/2014

Thank you Alan for all that info...very much appreciated.