We are waiting (and waiting) for the apple leaves to fall in order to begin pruning – but it just isn’t happening. If deciduous trees don’t drop their leaves as they should, we say we have a marcescent falll. Marcescent means the trees hold their leaves into winter. It is often triggered by a sudden change from warm to cold temperatures during the fall. Trees prepare for winter by absorbing nutrients from the leaves to store over winter. At the same time they to form an abscission layer at the base of the petiole or leaf stalk to enable the leaf to break away from the tree after the nutrients have been absorbed. If warm weather changes quickly to cold, it can kill green leaves before the abscission layer has formed and the leaves are “stuck” on the tree. They will eventually become unstuck, but this will take considerably more time.