Tree Colour - Time to take a closer look!
We talk about the delight of autumnal colour available from April through June each year, but late spring and early summer offer its own colour delight - you just have to look a little more carefully for it. While springs visual charms may be a bit more subtle than autumn, coming as they do after bare limbs and drab browns and greys of winter, they are just as good to see.
As trees break winter dormancy and their buds develop into various leaves, twigs, and flowers, foliage may change colours in varying combinations and intensities before turning to the basic early summer green. This whole process – from first swelling of flower and leaf buds through fruiting and full leaf expansion – occurs over many weeks and offers a changing array of colours, depending on a number of variables, including location, elevation, current growing conditions and of course the tree itself. The spring show is often red or variations through oranges and yellow – so it is noticeable particularly as we escape a dull and dreary winter.
Leaves are commonly tinged with some red when they first appear. Gradually, they turn green as they produce the pigment, chlorophyll. But this process requires light and warmth. If those newly emerged leaves are greeted by a cold snap or prolonged cloud cover, they can’t make the chlorophyll they require to be green and will remain coloured for an extended period of time.
I am told that a tree’s motivation for producing reddish new growth is to deter sucking insects which are discouraged by the colour red and therefore go seek food elsewhere. New spring growth is also folded and closed until there is enough warmth in the air to open to harness the energy of the sun and the making of chlorophyll.
There are some scientists in the US that suggest that the red colour also helps trees withstand cold and screens them from damaging ultraviolet rays and air pollution. Taking all of these factors into account, and whether right or wrong, overall this is a brilliant strategy particularly for a fresh spring leaf just getting started on a full growing season.
As an aside, the reds, purples, and colour combinations in between that decorate autumn foliage come from a group of pigments in the cells of leaves called anthocyanins. During the summer growing season, phosphate is at a high level. It has a vital role in the breakdown of the sugars manufactured by chlorophyll. But in autumn, phosphate along with the other chemicals and nutrients, move out of the leaf into the stem of the plant. When this happens, the sugar-breakdown process changes, leading to the production of anthocyanin pigments. The brighter the light during this period, the greater the production of anthocyanins and the more brilliant the resulting color display. When the days of autumn are bright and cool, and the nights are chilly but not freezing, the brightest colorations usually develop.
Anthocyanins temporarily colour the edges of some of the very young leaves in spring too as they unfold from their buds. On this page you will find some good examples of red foliage colour interest to keep a look out for this season.
Agonis flexuosa is an attractive medium sized tree with an elegant pendulous habit that looks fabulous in any landscape. As a taller variety fully grown, it will provide some shade in the summer months but this functionality is topped by its graceful, willow-like appearance. Soft and elegant, its weeping form adds softness to the landscape design. Smaller growing but exuding personality is Agonis flexuosa ‘Burgundy’ (above). Sort after for its rich burgundy foliage colour and weeping habit, it is a truly striking small feature tree.
Waterhousea floribunda 'Whisper'
Weeping Lilly Pilly
This is stunning spring specimen growing to a local height of 12 metres. Waterhousea ‘Whisper’ has a wonderful weeping pendulous habit with narrow linear green leaves most of the year. In early to late spring new growth has that vibrant reddish orange tinge and personally I think this is the time it is at its best. Used for large screening, its two-tone colourings are quite striking and unexpected. It has white flowers forming in summer followed by green fruits. More info...
Photinia robusta
Red Leaf Photinia
Another prominent red tinged hedging or screening tree depending on intended use is Photinia robusta. Also called Red Leaf Photinia, this is a hardy, small growing tree with small white flowers in summer followed by red fleshy fruit. Very noticeable in the urban landscape from early spring, it is characterised by strong red tipped leaves on fresh new growth, ultimately turning to green as the weather warms up. More info...
Agonis flexuosa
Willow Myrtle
This is an attractive medium sized tree with an elegant pendulus habit that looks fabulous in any landscape. As a taller variety fully grown, it will provide some shade in the summer months but this functionality is topped by its graceful, willow-like appearance. Soft and elegant, its weeping form adds a softness to the landscape design. Our stock looks great in 50 litre containers. More info...
Angophora costata
Smoothbarked Apple Myrtle, Rusty Gum
Angophora costata
This is a large evergreen tree with dense foliage and broad domed crown that is loved for its smooth bark, and large twisted limbs. Its bark is shed in large flakes in spring when the older pale grey bark makes way for new bark which is salmon-pink in colour. At this time, young foliage appears across the tree giving it a deep burgundy red tinge, gradually fading to green and providing an excellent contrast to the bark. Providing transient colour interest as well as shade, we have good numbers available in 50L, 100L and 150L. More info...
Cercis canadensis 'Forest Pansy'
This tree is an open, vased-shaped habit with upward branching. Brilliant reddish-purple large heart-shaped leaves amassed on the tree in spring slowly turn purplish-green over the course of summer. Its bark is brownish red fades to grey as the tree matures. This is a beautiful feature tree for small gardens and a very hardy one that will tolerate most soils and conditions. The choice of our stock is in 100 litre containers. More info...
Tristaniopsis laurina
Kanooka Gum
This tree is a real favourite this time of year. While not usually big enough to provide shade to sit under, it is another tree with that exhibits both interesting bark as well as transient foliage colour this time of year. Smooth light grey bark contrasts beautifully with the profusion of new reddish growth that shoots after the passing of winter. It is not due to seasonal reasons but more the awakening of new growth after a period of dormancy. For added interest, summer then brings masses of yellow flowers that sit tightly on the tree. We have good numbers in 40cm and 50 litre containers. More info...