The process of photosynthesis steadily degrades the supply of ­chlorophylls in foliage. Plants usually replenish chlorophylls during the ­summer months.

 When autumn arrives and the days are shorter or when plants are drought stressed, deciduous trees decrease chlorophyll pigment production, which allows other pigments in the leaf to become apparent, resulting in non-green coloured foliage. 

The brightest leaf colours are produced when days grow short and nights are cool but remain above freezing.

A variety of deciduous trees are ­suitable for planting to create brilliant displays of autumn colours. 

However, the actual selection will depend on the climatic conditions because certain trees are more suitable for colder, frosty areas. 

In the Maitland area, there are several trees that are most suitable and, as their leaves are now changing colour, it is the best time to select the trees you want to plant. 

Selecting trees that display their colours at nursery and garden centres will ensure the mature tree will create the desired effect.

The Chinese tallow wood (Sapium sebiferum) is one of the best trees for autumn colours in warmer areas. Trees reach up to eight metres tall. 

The autumn foliage ranges from crimson to yellow, orange and ruby-red. Colours will vary as the trees are generally grown from seed.

For large areas, liquidambars create beautiful displays in the pyramid shape. 

They are fast-growing trees and can reach 25 metrestall. Leaf colours include yellow, orange and scarlet to purple. New varieties have been developed.

The claret ash (Fraxinus “Raywood”) grows to about 20 metres tall. It has glossy green foliage that turns claret to deep purple in autumn. The foliage of the golden ash (Fraxinus excelsior “Aurea”) turns a clear yellow in autumn. It grows about 15 metres tall. An added feature is the yellow branchlets that have conspicuous black buds.

geoffh.gardening@gmail.com

Maitland and District Garden Club