Too often, poor planning, a lack of regular maintenance - such as pruning and shaping - or a combination of the two, results in towering, densely foliaged and unruly trees consuming valuable space in gardens. Another common problem is simply the planting of the wrong plants in the wrong place. These factors can culminate in undesirable future problems such as the uplifting of pavers and concrete, excessive shade, and excessive leaf litter collecting in both gutters and in the garden bed itself, smothering understorey plants.
Below, I have evaluated three small tree species perfect for small gardens, courtyards, or for planting within garden beds in larger parkland settings. The species I have chosen are all small trees, with modest root systems, and relatively open canopies; plants excellent for understorey planting. They all produce showy, unique flowers, and are all bird, bee and/or butterfly attracting, promising aesthetic flair whilst also performing valuable ecological functions.
1) Queensland Tree Waratah (Alloxylon flammeum)
If you’re in need of an ornamental tree species suitable for either a small garden bed in a residential block, or for a spot within a garden bed in a public park or garden, but are interested in something distinctive and unique, Queensland Tree Waratah (Alloxylon flammeum) could be the tree for you. A native of Queensland’s lush tropical rainforests, yet hardy and adaptable to colder, drier climates, Queensland Tree Waratah provides an open canopy of glossy emerald-green elliptical leaves (deeply lobed when juvenile) that are complemented nicely by showy red flower clusters in spring and early summer. If you desire a tree species that enables sufficient light and rainwater for understorey plants, Queensland Tree Waratah is a great option.
Exceeding 25m in its natural habitat, Queensland Tree Waratah is much shorter in cultivation, growing to only around 8-10m – perfect for smaller-sized gardens. A member of the largely Australian Alloxylon genus (within the Proteaceae family), the Queensland Tree Waratah is, as you may have guessed, so named due to its inflorescences resembling those of the iconic Waratah (Telopea sp.). Alloxylon is a small genus, scattered around the southern peripheries of the Pacific Rim, its origins lying in the Cretaceous period, when Australia, Antarctica and South America were connected by land. Queensland Tree Waratah is naturally restricted to the fertile Atherton Tableland west of Cairns, where basalt volcanoes began erupting about 3 million years ago, with the most recent set of eruptions said to have occurred as recently as 10 000 years ago. These eruptions, which flooded parts of the landscape with bubbling nutrient-rich basaltic lava, have resulted in dark rich soils – much of which is now used for agricultural crops. Despite its origins in the Queensland rainforest, with its rich basaltic soils and acute humidity, the Queensland Tree Waratah is very versatile and adaptable, growing at least as far south as Melbourne, Victoria.
Care & Cultivation:
In terms of care, Queensland Tree Waratah is fairly low-maintenance. It grows best in moist, friable, well-drained soil, but can withstand heavier clays and seasonal waterlogging. It will also withstand dry spells, but as a coping mechanism, will likely not flower, or at least produce less flowers during these periods. Suffering from no diseases of note, the only problems that may plague your Tree Waratah are: root-zone disturbance (in general species in the family Proteaceae do not respond well to root disturbance); and feeding with a high phosphorus fertiliser, which may result in leaf burning. It can be propagated readily from seed, and can also strike readily from cuttings. When striking from cuttings, ensure you use hardened new growth and apply a hormone solution specifically formulated for hardwood cuttings before planting.
Depending on what look you are going for, Queensland Tree Waratah can provide either a beautiful focal point in a small garden or work as part of a broad-scale landscape concept. I have used it in association with an understory of wiry native grasses, such as Longhair Plumegrass (Dichelachne crinita), Kangaroo Grass (Themeda triandra) and Spear grass (Austrostipa sp.) to great effect. It also looks sensational planted out with a shrub layer consisting of grey and green leafed species such as Roundleaf Correa (Correa reflexa var. nummulariifolia), Westringia fruticosa ‘Deep Purple’, and Yellow Buttons (Chrysocephalum apiculatum). If you’re more interested in mimicking a rainforest enclave, a number of lush bright green Dianella caerulea ‘Little Jess’, a couple of Water Ferns (Blechnum sp.), and an assemblage of dense lime-green groundcovers works well. I have found that White Root (Pratia purpurescens) and Native Violet (Viola hederacea), and the larger-leaved Snake Vine (Hibbertia scandens) really complement Queensland Tree Waratah.
2) Queensland Firewheel Tree (Stenocarpus sinuatus)
Another member of the Proteaceae family (ok, it’s fair to say I do have a slight obsession with Proteaceae!), the Queensland Firewheel Tree happens to be one of my favourite tree species. Another native of Queensland and extending as far north as Papua New Guinea, Queensland Firewheel Tree takes its name from the wheel-like arrangement and flame-red colouration of its stately inflorescences. I have chosen Queensland Firewheel Tree because much like the Queensland Tree Waratah (Alloxylon flammeum) discussed above, it is a versatile and adaptable tree, flourishing in a range of climates and soil conditions. Whilst the conspicuous flower clusters are the obvious attraction of this species, its leaves – which come either lobed or entire – also provide an attractive glossy green display, giving your garden that lush undomesticated rainforest feel. Perfect for small gardens, courtyards and for planting within garden beds in more open park settings, this species provides a point of interest due to its striking and ancient lobed leaves and its dazzling red flowers.
A 30m tall tree in its natural habitat, Queensland Firewheel Tree is noticeably smaller in cultivation, particularly in the cooler climates of Sydney and Melbourne, generally not exceeding 15m. A member of the Stenocarpus genus, which extend from New South Wales, north to Queensland and west through the Northern Territory to Western Australia, the Queensland Firewheel Tree has been used by local governments as a street tree in Brisbane, Melbourne and Sydney. In terms of its evolutionary history, the ancient ancestors of the Proteaceae family originated on the supercontinent of Gondwana, which progressively broke into Africa, Australia and South America, giving rise to the great variety of Proteaceae we enjoy across these three continents today. The Queensland Firewheel Tree is intriguing because it exhibits foliage typical of the ancestral forms, which other species and genera have since abandoned, such as its large lustrously green leaves.
Care & Cultivation:
Queensland Firewheel Tree is tolerant of full-sun to partly-shaded positions within the garden. It can handle open sites exposed to desiccating winds, but in my experience grows best in a slightly sheltered position. In terms of soil type, it is best suited to a rich loamy soil, but can grow in most slightly acidic to neutral soils, granted they are medium-to-well drained. If improving the ecological attributes of your garden is something you are interested in, I have found that Queensland Firewheel Tree attracts everything from bees and nectar-feeding birds, to butterflies and lady-bugs. It can be propagated readily from seeds, and also from cuttings.
I have successfully used Queensland Firewheel Tree in a number of landscape settings: from screening trees to feature plants. I have found it useful in providing tall screens, useful for blocking out large buildings such as apartment blocks and other unsightly structures, particularly in small inner-city courtyards. They are great for this purpose because the foliage is concentrated at the top of the tree, allowing for the planting of understory plants. Because they don’t tend to exceed 15m in height in cultivation, they can also be used within garden beds as an ornamental tree or as street trees. They look great towering over an understory of strappy-leafed lush-green plants such as Lomandra longifolia ‘Tanika’, and Dianella caerulea ‘Little Jess’, or for colour contrast, the grey-leafed Lomandra confertifolia ‘Seascape’ or Dianella revoluta ‘Little Rev’ interspersed with Creeping Boobialla (Myoporum parvifolium).
3) Golden Penda (Xanthostemon chrysanthus)
Hailing from the coastal rainforest of north Queensland from Townsville to Cape York, the Golden Penda (Xanthostemon chrysanthus), as the name might suggest, produces a profusion of dense, showy clusters of golden flowers near the ends of its branches predominately in summer and autumn. A member of the Myrtaceae genus, which includes Eucalyptus, Melaleuca, Leptospermum, and other iconic Australian genera, the Golden Penda is definitely one of the lesser known, and yet one of the most spectacular of the Australian Myrtaceae cohort. Growing in tropical, sub-tropical and temperate areas, Golden Penda is very adaptable, so long as it is planted in a sunny position in a well-drained soil.
Originally lumped into the Metrosideros genus by Victorian Government Botanist Ferninand von Mueller in 1864, Golden Penda was reclassified in the genus Xanthostemon by George Bentham in 1867. Growing to 15m in the wild, Golden Penda is much more compact in cultivation - growing to a mere 5m. The Xanthostemon genus grows naturally in New Caledonia, Australia, the Soloman Islands, the Phillipines, New Guinea and Indonesia. In terms of its evolutionary history, Xanthostemon, as a member of the Myrtaceae family, can be traced back to Antarctica, where the fossil pollen of primitive Myrtaceae taxa has been found. Although initially evolving in the primordial moist rainforest climates of the Cretaceous period, the Myrtaceae family now occupies a large variety of environments, including along Australia’s coastal dune systems (think Coastal Tee Tree – Leptospermum laevigatum), and into the arid interior (think Ghost Gum – Corymbia aparrerinja).
Care & Cultivation:
Producing a bounty of flower-heads at various times of the year, Golden Penda can really light up a garden in those cooler months when many other species are not flowering. Whilst being the most widely cultivated of the Xanthostemon genus due in large part to its exuberant flowers, I have not noticed this species being used in gardens and park landscaping as much as I believe it should be. A perfect substitute for the more commonly planted Wattle (Acacia sp.), particularly in sub-tropical and tropical climates, Golden Penda suffers from no major pest or disease problems and flourishes best when planted in a sunny spot, in a moist well drained soil. It is also a great species for attracting birds, butterflies and other beneficial insects to your garden. Ensure you prune to the desired shape, removing the lower branches in order to encourage a tidy crown, and pruning leading stems to encourage more profuse flowering and greater density.
If you’re interested in creating a striking colour contrast that will really set your garden apart (and alight!), a canopy of Golden Penda, either planted as a single ornamental tree in a small garden, or as a set of trees in a thematic parkland environment, can work wonders. In the past I have employed Golden Penda in association with an assemblage of smaller shrubs and groundcovers to brilliant floristic effect. One idea you might be keen to try at home includes using Golden Penda as an ornamental tree in the back corner of your garden, then planting a swathe of Native Ginger (Alpina caerulea) as an understory, with a border featuring either Purple Dampiera (Dampiera purpurea), Purple Fan-flower (Scaevola aemula) or the ever-dependable Native Violet (Viola hederacea), or a combination of these. By positioning Golden Penda, with an understory of lush-green large-leaved Native Ginger, and one of or a combination of the groundcovers mentioned above, I can guarantee an impressive and varied display of flowers, foliage, and form.
©Allen Henderson 2013