"Trees!"

Trees are vital in gardens.
Sunday, 11 February 2024     

Lagerstroemia indica

Summer is a good time to remember to show appreciation for trees, especially during the horror heat of last Sunday and Monday in Sydney. The shaded sections of my garden seemed to cope better on the whole than those bearing the brunt of the burning sun. How I wish I had planted more trees when we first came to this garden 30 years ago! Only later did I realise it is best to think about these large plants first, before adding the smaller plants such as lower-growing shrubs, perennials, annuals, bulbs and groundcovers! As well as providing shade for people and plants, trees help shape the three-dimensional space to create the permanent architectural framework of a garden, without which it would be rather flat and boring. A suitable tree can help frame a view or the garden as a whole, and can link the garden to the scale of the dwelling. Trees can help give privacy and screen off less-than-optimum views. Some small trees with a naturally distinctive arching or weeping shape can be a feature in themselves.

Trees sequester carbon dioxide from the atmosphere during photosynthesis and convert it into carbon as they grow, storing it in their trunks, stems, leaves and roots. Trees also help reduce stormwater runoff in several ways - for example, by intercepting falling rain and holding it on leaves and bark, which is gradually released to the soil below; by absorbing rain in the organic layer that usually forms under a tree from fallen leaves; and by roots that hold the soil in place and soak up the stormwater.

As well as their utilitarian value, trees also often have beautiful flowers, foliage and bark, and offer habitat to birds, animals and insects in the garden. Deciduous trees are probably the ideal choice if possible: they are delightful in every season, from the unfurling of their brand-new leaves in spring; the welcome shade they provide in summer; the autumn colour in their leaves; and the intricate tracery of their bare branches in winter, which allows the sun to get through and can cast interesting patterns on walls or lawns. Additionally, the soil under a deciduous tree will benefit from the decomposition of its fallen leaves each year, giving a moist, humus-rich profile that will help under-plantings to grow well.

When choosing a tree, also take into account its shape: weeping or arching or spreading trees give more shade than those with a columnar or vase shape. The size of the leaves is also directly related to the amount of shade cast, as is the density of the foliage. If you want to have a garden bed beneath your tree, most shade-loving plants prefer the lighter summer shade of deciduous trees to the heavier shade of evergreen trees. Also, note that shallow-rooted trees will be harder to plant under than those with deeper roots. It's worth thinking about fallen fruit, nuts and seedpods from the tree you choose and whether these will be an issue. In general, though it is tempting to plant a fast-growing tree to get a quick result, in the long run I advocate choosing ones that may grow a bit slower but will have a longer life than the tempting 'hares', which often exhaust themselves after a few years.

Of course, the ultimate height of the tree is a vital point to consider as many are just not suited to suburbia as they get too tall (Liquidambar, I am talking about you) and others sucker in a horrible way (think Robinia pseudoacacia 'Frisia'). Some suggestions for a small tree are the Chinese pistachio Pistacia chinensis (ht to 8 m); Japanese maples (Acer palmatum cultivars, ht 3.5-4.5 m: though the very fancy ones tend to burn in our summer); Syzygium cultivars (ht 5-8 m, lilly pilly); Dais cotinifolia (ht 3-6 m, pompon tree); Malus ionensis 'Plena' (ht 5-6 m, crab apple); Magnolia x soulangeana (ht 5-8 m, tulip magnolia), with exquisite large goblet- or saucer-shaped flowers of pink, white or deep purple from late winter to mid-spring; and crepe myrtles (Lagerstroemia indica, ht to 8 m).

Of the trees flowering at the moment, crepe myrtles have been simply stunning this summer, taking the heat in their stride, with generous trusses of soft, crimped blooms in colours of pinks, white, reds, mauve and deep purple, forming a pretty backdrop to summer border flowers. Petals fall to make a carpet below. The trees have wonderful smooth young bark in attractive patterns, revealed each summer after the old bark has peeled off, and have a beautiful open vase-like shape if not pruned. Traditionally, the trees were pruned very hard every winter to ugly stubs to create a mass of bloom on straight stems fanning out from the pruning points, but these days we tend to appreciate more the natural shape of the tree left to its own devices. The leaves turn to pretty golden and red tints in autumn in Sydney, and all-in-all the crepe myrtle is a good choice for a small garden. Older varieties were subject to powdery mildew, but newer ones (such as the 'Indian Summer' hybrids) are supposedly resistant. There are a number of named hybrids, including multi-stemmed shrubby varieties around 3-4.5 m tall (such as white 'Acoma' and bright pink 'Hopi'). The new dark-leaved specimens seem a bit unpredictable in Sydney, but I have seen some of them thriving.

Small hybrid grafted gums (one of their parents being Corymbia ficifolia) are quite spectacular in full bloom and these are a better choice for gardens than most gum trees. 'Summer Beauty' is pink, and 'Summer Red' has vibrant scarlet flowers. The intricacy of the blooms is simply exquisite. Later, large woody seedpods form, which are also attractive. These grafted gums are easier to grow in Sydney than the original species they were bred from and are quite compact trees, growing to 5 m or a bit taller. They are reportedly drought tolerant.

A Queensland rainforest native, the ivory curl-flower tree (Buckinghamia celsissima) is quite stunning in a garden near to mine at the moment - a mass of perfumed long blooms with curling petals, like a cross between a bottlebrush and a grevillea; it belongs to the same family as grevilleas, the Proteaceae. It grows to a height of 6-8 m in a garden setting and likes a reasonably rich, well-drained soil with at least part sun. Many native rainforest trees grow very well in our climate, and their glossy leaves allow them to fit in well with other exotic plantings. Backhousia citriodora (ht 3-8 m, lemon-scented myrtle) and Elaeocarpus reticulatus (ht 7-9 m, blueberry ash) grow well - they can be pruned to keep them more compact.

Blog first posted 5 February 2009; updated 11 February 2024.


 Reader Comments

1/8  Margaret - 2122 (Zone:10 - Warm Temperate) Saturday, 07 February 2009

I, too, love crepe myrtles, mine are in full blowsy flower now, in colours of pink, lavender and mauve, plus the benefit of a back neighbours which are dark pink and a magenta (both trees came from cuttings supplied by me!) Unfortunately, I dont have any other trees in bloom now.


2/8  Caevan - 2077 (Zone:10 - Warm Temperate) Monday, 23 February 2009

At Last


3/8  Jil - 5126 (Zone:10 - Mediteranean) Monday, 09 March 2009

The flowering gums here on the mornpen are just stunning. I wish you could see them! Brilliant scarlet, all shades of pink, orange, just breathtaking and alive with birds. Now, what do you think about the dreaded pittosporum (such a weed here) suddenly flowering after that heatwave?


4/8  Paula - 4209 (Zone:11A - Sub-tropical) Monday, 15 February 2021

Crepe Myrtles are an absolute favourite with me. When the flowers drop and the seeds are forming I trim those heavy heads back and receive another flush of flowers during autumn.


5/8  Janet - 2322 (Zone:10 - Warm Temperate) Monday, 12 February 2024

I have the most beautiful Crepe Myrtle which I let grow into it's natural shape but unfortunately the whole of my garden was attacked by the Monolepta Australis beetle and my Crepe Myrtle was badly affected as were many other plants. This pest has now migrated south all over NSW. I am now trying to find solutions to my problem! So gardeners keep your eye's peeled for this destructive pest. Janet, that beetle sounds terrifying. I have never heard of it before. Thanks for alerting us. Deirdre


6/8  Betty - 3104 (Zone:10 - Mediteranean) Monday, 12 February 2024

Nine years ago we were in the U.S.A. in Virginia and one town had the Crepe Myrtle as its street tree (around Jamestown/Williamsburg). What a beautiful sight! It sounds wonderful, Betty! Deirdre


7/8  Shaun - 2075 (Zone:10 - Warm Temperate) Monday, 12 February 2024

over 15 years I have transformed my previous backyard velvet green lawn into Oz. natives, including 3 blueberry ash, 2 summer reds and 2 stunning buckinghamia, Bee heaven, since late January. How I love my trees shade from due western blazing sun, trees I chose, love and now the late divine summer flowering, Shaun That sounds fantastic, Shaun! Deirdre


8/8  Margaret - 2122 (Zone:10 - Warm Temperate) Monday, 12 February 2024

I still love crepe myrtle trees and have a large one in my back garden, which provides welcome shade during these hot periods. Without it shade my shade garden would not exist. My mock orange, in another area is growing taller, providing shade for some of my begonias. Thank you to Janet for information re the bug attacking the c/m, so far my trees are free from it. Will keep a watchful eye. Yes your crepe myrtle is magnificent and creates your shady oasis in that area of the garden. Deirdre


Make a comment

* You can only post comments on Blogs if you are signed in. If you are already registered please go to the Home page and Sign-In first. If you are not an iGarden member please click here to register now.

My eBooks (PDF)

Plant of the week

Most-recent blogs

Early-autumn daisies
24 Mar 24
Daisies contribute to the beauty of early autumn in Sydney gardens.

Paradise revisited
17 Mar 24
I revisit a stunning Sydney acreage garden.

A bromeliad solution
10 Mar 24
Bromeliads provide a solution to difficult, dry, shady spots in Sydney gardens.

Refreshing whites for hot days
03 Mar 24
These white flowers add a touch of coolth,

Grooming the garden
25 Feb 24
Prepare your garden for a renewed lease of life in early autumn.

Previously at this time

2009 - 12 Feb
2010 - 14 Feb
2011 - 13 Feb
2013 - 10 Feb
2014 - 16 Feb
2015 - 08 Feb
2016 - 07 Feb
2017 - 12 Feb
2018 - 04 Feb
2019 - 17 Feb
2020 - 16 Feb
2021 - 14 Feb
2022 - 13 Feb

Promotions