Dozens of Illawarra local natives are suitable as street trees. Many are tried and proven performers in this region or further afield. Others offer huge but untested potential. Widespread use of local tree species, particularly trees from the rainforest, has the potential to create a unique sense of place in the Illawarra region, bringing a flavour of the escarpment down into the city and suburbs. It will also help restore biodiversity, by providing more suitable habitat for local fauna.
Beautiful small trees like Black Plum (Diospyros australis), Coast Canthium (Cyclophyllum longipetalum) and Yellow Wood (Sarcomelicope simplicifolia) would make handsome additions to a streetscape. Larger species such as Native Laurel (Cryptocarya glaucescens), Murrogun (Cryptocarya microneura) and Brush Wilga (Geijera salicifolia) would be hardy and attractive replacements for the widespread and weedy Camphor Laurel. Where space allows, and a deciduous tree is required, the iconic Red Cedar (Toona ciliata) could be planted.
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| Black Plum (Diospyros australis) growing in a large garden setting. Image by Narelle Happ. |
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| Red Cedar (Toona ciliata) is a great street, landscape or specimen tree. The plant shown here is growing in Kings Park, Perth, Western Australia. Image by Emma Rooksby. |
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| Brush Cherry (Syzygium australe) is a classic and tested street tree, with a neat rounded crown of dark green foliage. Image by Mithra Cox, reproduced under CC BY-NC 2.0. |
Many rainforest tree species of the Illawarra region are hardy and adaptable, growing well in the same conditions as average introduced garden plants. The idea that rainforest plants require special conditions and treatment to survive is a misconception. If conditions are particularly harsh, that is hot, dry and exposed, then some initial care after planting may be necessary (as with most garden plants), but under average Illawarra conditions they will grow well.
Rainforest tree forms in the landscape
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| Red Ash (Alphitonia excelsa) is an outstandingly tough local rainforest tree. It can be seen on verges around the region, such as in Mount Pleasant. Image by Mithra Cox, reproduced under CC BY-NC 2.0. |
Rainforest trees of Illawarra are very good landscape subjects. They can be planted individually to be used as modular elements forming various shapes, sizes, colours and textures, or they can be used together in rows, strips of any width, blocks of planting and whole forests if the need arises. Heights of species vary from 2m to 20m and more. Shapes vary from narrow to very broad. Colours vary from pale green to dark, with many having attractively coloured new growth. Textures range from large leaves up to a metre long, right down to the small and narrow leaves of the Whalebone Tree (Streblus brunonianus).
Tree height and sunlight exposure
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| Whalebone Tree (Streblus brunonianus) with its small, narrow leaves, forms a compact bushy small tree. Image by Leon Fuller. |
When planted in the open, trees will generally grow shorter and broader than in forest formation. So if trees are required to grow tall then plant them in groups. If the height of any species is to be kept to a minimum then it needs space around it to reduce the need to go up for light.
Eucalypts as street trees
Because of the good rainfall and subtropical conditions in Illawarra, the indigenous eucalypts (including Angophoras and Corymbias) in their natural forest home, mostly grow as big forest trees and are not suitable for most streets. However, they can be very useful in large open spaces such as public parks and reserves. They are also too large for most streets. Yet in some situations in the street they are just the tree needed to restore a sense of scale to a landscape, for example where there are very big or congested buildings.
Some suitable species
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| Swamp Mahogany (Eucalyptus robusta) is the smallest local eucalypt, and grows well on verges around the region. Image by Mithra Cox, reproduced under CC BY-NC 2.0 |
Local rainforest and woodland tree species that are most suitable as street trees are listed below. Specific limiting factors are mentioned where relevant. Sizes shown are indicative for cultivated trees grown in open conditions. Small=under 10m, Medium=10m-20m and Large=over 20m high.
Note: This list does not include some very familiar and much used street trees such as Tuckeroo (Cupaniopsis anarcardioides), Blueberry Ash (Eleocarpus reticulatus) and Water Gum (Tristaniopsis laurina). These species are all over-used in the region, and Tuckeroo in particular has a tendency to become weedy.
Species
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Summary
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Size (S/M/L)
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Lilly Pilly (Acmena smithii)
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A relatively hardy tree with a broad, dense, rounded crown. Proven in the region.
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S
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Black She-oak (Allocasuarina littoralis)
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A small She-oak with a neat, conical shape, often only 3m to 6m high. Currently not much used.
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S
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Forest Oak (Allocasuarina torulosa)
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A beautiful tree, fast-growing and drought-hardy. Under-used at present.
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S
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White Aspen (Acronychia oblongifolia)
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Some variability in crown shape but usually a rounded crown. May need supplementary water. Grows best if root zone is grass-free.
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S
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Native Quince (Alectryon subcinereus)
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An adaptable tree usually with a broad dense crown. May need supplementary watering during establishment.
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S
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Red Ash (Alphitonia excelsa)
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Hardy tree with showy flowers and foliage. A proven tree in the region.
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M
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Bangalow Palm (Archontophoenix cunninghamiana)
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Fast-growing given ample water. Best of the two local palms to plant in the street.
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M
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Grey Myrtle (Backhousia myrtifolia)
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Suitable and very hardy but may be slow-growing. It is not much tried. [Similar to Lilly Pilly in growth rate but does not drop messy soft fruit.]
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S
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Brush Bloodwood (Baloghia inophylla)
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A beautiful, hardy tree with strong potential. Medium growth rate.
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S
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Coastal Banksia (Banksia integrifolia)
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An attractive tree already used in the region. Hardy and long-lived.
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S/M
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Illawarra Flame Tree (Brachychiton acerifolius)
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A proven performer and local favourite. Flowering may be sporadic and the tree is semi-deciduous, losing some or all of its foliage in some years.
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S
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Kurrajong (Brachychiton populneus)
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The smaller cousin of the Flame Tree, and at least as hardy, with an attractive ‘lollypop’ shape. Needs almost no maintenance.
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S
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Willow Bottlebrush (Callistemon salignus)
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A distinctive and proven local tree with pink new growth and neat crown. May need extra water until established.
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S
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Native Celtis (Celtis paniculata)
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A beautiful, shapely small tree suitable for all well-drained, friable soils.
Strong potential but is currently little grown.
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S
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Coachwood (Ceratopetalum apetalum)
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Related to the NSW Christmas Bush, though less showy. When grown in the open it rarely reaches more than 10m high. May need supplementary water.
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S
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Oliver's Sassafras (Cinnamomum oliveri)
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Strong potential but it is currently not much used. It has distinctive reddish new growth.
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M
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Murrogun (Cryptocarya microneura)
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A hardy species with a neat and fairly narrow crown. It is not currently much grown.
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S
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Brush Canthium (Cyclophyllum longipetalum)
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Suitable and very attractive though not currently much used.
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S
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Black Plum (Diospyros australis)
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Suitable with a handsome pyramidal shape. Not much used in the region at present.
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S
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Myrtle Ebony (Diospyros pentamera)
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A suitable and strong tree, but currently little used. Slow but steady growth rate.
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S
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Pigeonberry Ash (Elaeocarpus kirtonii)
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Hardy rainforest tree with a dense, rounded canopy. Its height limits its applications.
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M
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Red-fruited Olive-plum (Elaeodendron australe)
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Slow-growing small tree, usually with an attractive rounded crown.
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S
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Bonewood (Emmenosperma alphitonioides)
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Neat tree with straight growth habit and bright orange fruit. Vulnerable to borers if planted in groups. Single planting only is recommended.
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S
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Ribbonwood (Euroschinus falcatus)
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A shapely and hardy tree. Not much tried in the region to date.
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S
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Brush Wilga (Geijera salicifolia)
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A small drought-hardy tree. With good potential, but not used to date in the region.
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S
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Cheese Tree (Glochidion ferdinandi)
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Attractive small tree with spreading, rounded crown.
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S
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Guioa (Guioa semiglauca)
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Very tough tree that can cope with most conditions across the region.
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S
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Bolly Gum (Litsea reticulata)
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A Suitable but currently little grown and performance in cultivation in the region is untested.
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M
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Bracelet honey-myrtle (Melaleuca armillaris)
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Fast-growing and hardy tree to around 5m, with a spreading crown of small dark-green foliage. Currently not much grown.
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S
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White Feather Honey-myrtle (Melaleuca decora)
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A very hardy tree that will cope with tough conditions including heavy clay soil and waterlogging. Dense dark-green crown.
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S/M
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Snow-in-Summer (Melaleuca linariifolia)
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Small tree proven in the region, with masses of fluffy white flowers.
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S
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Hairy-leaved Doughwood (Melicope micrococca)
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Beautiful small tree with a dome-shaped crown. Well-suited as a street tree.
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Boobialla (Myoporum acuminatum)
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Fast-growing and hardy small tree to 5m. May need pruning to ensure tree rather than shrub form.
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S
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Black Apple (Planchonella australis)
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Attractive small tree. Its large fleshy fruit may limit its uses e.g. in paved areas.
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S
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Plum Pine (Podocarpus elatus)
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Robust slow-growing and hardy tree with a good track record. Can be pruned.
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S/M
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Celery-wood (Polyscias elegans)
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Hardy and fairly fast-growing. Attractive palm-like spreading crown.
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S
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Yellow Wood (Sarcomelicope simplicifolia)
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Tough much-branched small tree with a broad crown. Suitable but currently little used.
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S
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Crab Apple (Schizomeria ovata)
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Strong potential but untried. In cultivation it is a much smaller tree than in natural rainforest settings, and typically reaches 15m.
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M
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Flintwood (Scolopia braunii)
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Small tree with a neat rounded crown. Minor tendency to sucker and prefers relatively sheltered conditions. Not much used at present.
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S
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Scrub Beefwood (Stenocarpus salignus)
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Ornamental, slow-growing small tree. Suitable but not currently much used.
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S
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Whalebone Tree (Streblus brunonianus)
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Suitable and very hardy. Tends to have a shrubby form, particularly when young. May defoliate in extended dry conditions, so will benefit from extra watering.
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S
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Turpentine (Syncarpia glomulifera)
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Suitable, somewhat slow-growing and eventually a medium or large tree. Does not drop limbs and is resistant to termites, but has large fruit.
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M/L
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Brush Cherry (Syzygium australe)
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Proven local performer with a neat rounded ‘lollypop’-shaped crown and edible red fruit.
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S
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Blue Lillypilly (Syzygium oleosum)
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A very attractive small tree suitable as a street tree. Availability may be limited.
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S
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Magenta Cherry (Syzygium paniculatum)
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Suitable and very attractive small tree but availability may be limited as the species is threatened regionally.
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S
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Red Cedar (Toona ciliata)
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An under-used but iconic local species. Grown in the open it is not a large tree.
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S/M
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Mountain Water Gum (Tristaniopsis collina)
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Untried but strong potential and an attractive tree. Relatively slow growth and may be multi-stemmed (like T. laurina).
|
S
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Some eucalypts suitable for growing in larger areas across the region are listed below. Small=under 10m, Medium=10m-20m and Large=over 20m high.
Species
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Summary
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Size (S/M/L)
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Cabbage Gum (Eucalyptus amplifolia)
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An extremely adaptable tree, suitable for many sites and conditions. Characterised by a fairly coarse crown.
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M
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Coast Grey Box (Eucalyptus bosistoana)
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A fast-growing and long-lived large eucalypt with a fine-textured crown and attractive bark.
|
L
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Grey Ironbark (Eucalyptus paniculata)
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An attractive eucalypt that has thick grey furrowed bark and a dense, spreading and sometimes irregular crown.
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M
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White-topped Box (Eucalyptus quadrangulata)
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A handsome medium to tall tree for large spaces.
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M, L
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Swamp Mahogany (Eucalyptus robusta)
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A small tree with appealing bright green foliage and a broad, dense crown. Suitable as a street tree in the right position.
|
S
|
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| The majestic Cabbage Gum (Eucalyptus amplifolia) is suitable for large-scale landscaping projects. Image by Byron Cawthorne-McGregor. |
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| Local palms make great street trees in the right situation. Bangalow Palms (Archontophoenix cunninghamiana) are used to advantage in landscaping at the University of Wollongong and the Wollongong Botanic Garden. Image by Scott Miller ©. |
Top street trees
These species will cope on verges in almost any urban or suburban conditions in the Illawarra area. They are versatile, moderately fast or fast-growing and most are small trees.
Species
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Summary
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Size (S/M/L)
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Native Quince (Alectryon subcinereus)
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An adaptable tree usually with a broad dense crown. May need supplementary watering during establishment.
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S
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Red Ash (Alphitonia excelsa)
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Hardy tree with showy flowers and foliage. A proven tree in the region.
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M
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Coastal Banksia (Banksia integrifolia)
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An attractive tree already used in the region. Hardy and long-lived.
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S/M
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Willow Bottlebrush (Callistemon salignus)
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A distinctive and proven local tree with pink new growth and neat crown. May need extra water until established.
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S
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Native Celtis (Celtis paniculata)
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A beautiful, shapely small tree suitable for all well-drained, friable soils.
Strong potential but is currently little grown.
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S
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Murrogun (Cryptocarya microneura)
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A hardy species with a neat and fairly narrow crown. It is not currently much grown.
|
S
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Brush Canthium (Cyclophyllum longipetalum)
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Suitable and very attractive though not currently much used. Availability may be a problem.
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S
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Myrtle Ebony (Diospyros pentamera)
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A suitable and strong tree, but currently little used. Slow but steady growth rate.
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S
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Cheese Tree (Glochidion ferdinandi)
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Attractive small tree with spreading, rounded crown.
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S
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Guioa (Guioa semiglauca)
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Very tough tree that can cope with most conditions across the region.
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S
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Snow-in-Summer (Melaleuca linariifolia)
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Small tree proven in the region, with masses of fluffy white flowers.
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S
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Plum Pine (Podocarpus elatus)
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Robust slow-growing and hardy tree with a good track record. Can be pruned.
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S/M
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Yellow Wood (Sarcomelicope simplicifolia)
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Tough much-branched small tree with a broad crown. Suitable but currently little used.
|
S
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Flintwood (Scolopia braunii)
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Small tree with a neat rounded crown. Minor tendency to sucker and prefers relatively sheltered conditions. Not much used at present.
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S
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