Maple Trees Have Yellow Leaves After Transplanting

Q: I transplanted two maple trees from my lot at Bent Tree. They were small
and exhibited beautiful red leaves. But here after several years they only turn a
pretty yellow…no scarlet. Why would that be? 

A: As you know, tree leaves change color as light levels and temperatures
drop in the fall. Green chlorophyll disappears and the pigments that produce
yellow, orange and red, which were there all along, become visible. Fall leaf
color on a tree is determined by the interplay of light, temperature, stress, and
the pH of the leaf sap. In Bent Tree, the trees were probably unstressed and
were growing in an environment that favored production of anthocyanin in fall
so the leaves turned red.
But now they are growing in a different temperature and light environment
and that is likely the reason they are yellow. There are maple tree varieties that
have been selected to be more consistent in their fall color in varied
conditions. ‘Autumn Blaze’ and ‘October Glory’ are examples.
If you simply dug two random pretty trees in Bent Tree, they simply were
unable to replicate their leaf color here in DeKalb County.