Joni Mitchell once sang about 'putting all the trees in a tree museum and charging everyone a dollar and a half just to see them' but at Westonbirt Arboretum they charge 9 quid and I pop back there every now and again to marvel at the autumn colours and to relive some of my gardening roots. For it was here I first saw a blue spruce, a larch and an Acer Palmatum - and I was inspired to plant specimens in the garden of the house where I was brought up. The Acer is still going strong 36 years later - I drive by it occasionally.
The other notable tree, Calocedrus decurrens, I've not planted yet and don't know why it isn't seen more in parks and gardens. In its native California it grows big and wide but in the UK climate it goes for tall and very thin which means you get a lot of impact without taking up space and blocking the sun.