Autumn Glory at Araluen

Why the colours?

Deciduous trees and shrubs protect themselves from cold by shedding their leaves in autumn (called ‘abscission’).  As soon as the length of darkness increases during March and April at the beginning of autumn, these plants begin withdrawing from the leaves all the nutrients, sugars and other plant chemicals essential for future growth. These are saved and stored in roots and woody parts of the plant to use in the spring when many of these plants flower before their new leaves appear. Not all pigments can be withdrawn from the leaf structure and those remaining may cause some leaves to develop bright colours before finally falling.  Not all deciduous trees develop these colours.  Some just go brown before falling. Others may turn red, purple and many shades of yellow, gold and orange.   

You may also notice coloured hips on some of the roses though only a few roses produce autumn colour in their leaves.

When do the trees colour?

Genetics play a major role in the timing of the leaves falling and the sequence of species from early to late in the season.  Some lose their leaves in early April while others hold their green leaves before colouring later in May and even June.

What about the Weather?

The weather affects the intensity and duration of the display.  The best colours develop when the weather is dry and calm with cold nights and cool days.  Temperatures especially at night and in the early morning are cold enough in the Park to trigger colour formation.  However, in windy wet weather the leaves are blown off the trees often before significant colour can develop or hold on the trees. So the colours may vary during the season depending on rainy spells and the display may be better some years than others.