On 29 Oct, 17:36, "dafs" wrote:
I bought this in November 2003, when the leaves were extraordinarily
beautiful shades of red.
It has prospered and grown into an attractive tree, but has never again
shown any red in the leaves in autumn. They remain stubbornly green until
they fall off.
Is there anything I can do to bring back its radiance next autumn, please?

The weather! Low temps destroy chorophyll and let the caratenoids
(yellow pigment) show through. If the trees are staying in an above
freezing environment, this will promote anthocyanin (red, blue and
purple pigments). These pigments are formed from sugars, the more
sugars, the more colours. When conditions are dry, there's more
concentration of sugar in the sap, more light and low temps promotes
even more. The best colours are therefore achieved with a dry,
bright, sunny days with cool nights after a dry august/sept.

Unless you can change the weather ... but you could make sure your
tree is not overcast - shadows/shade might stop the making of sugars.
Make sure it's not waterlogged either or too protected by side high
fences etc.

In the North West we're having the most wonderful autumn that I can
remember. It's simply fantastic ) Where are you?