This was in The Times today!
'Well, here’s how to ensure your maple thrives in its new home. First, it’s important to remember that these are trees of sheltered glades. Think of the famous Maple Glade deep in the woods at Westonbirt Arboretum in Gloucestershire and the maples at the Savill Garden in Windsor, Berkshire. Shelter and light shade are what’s required. Not heavy all-day shade, not solid overhead shade, but shade from the hot midday sun.
In a glade there’s a ring of coolness under the taller trees. Cool part-shade, and with open space across the glade for rain to fall and keep the roots gently moist at all times. There are lots of fallen leaves too, so a natural mulch of leaf mould, year in year out. And in an ideal world a neutral or slightly acidic, well-drained soil.
How to replicate all that in a garden? Find a spot out of sneaky winds that would raddle that soft, emerging foliage, and sheltered enough to keep off a degree or two of those depressing late frosts that come when the buds have burst and blacken young foliage.
The more thread-like or pale or variegated the (mature) leaf, the more the plant needs to be planted out of the hot sun. West-facing is always good but even a very open position where all the light is still indirect will be OK. Purple and green varieties need good light to keep their colour bright.
Always prepare a good planting hole and never plant maples too deep. They hate it and incline to root disease. But here’s the most important advice: at the start, treat your maple like a delicate bedding plant and harden it off before you plant it.
I know, it’s a very hardy plant, but it has been raised in the shelter of a nursery, maybe in a semi-shaded tunnel, where its growth will have started unnaturally early and it will be extraordinarily well fed.
So when you get it home, give it a week in the shade, out of all wind, then none of that delicate foliage and fine twiggery should scorch or shrivel.'