The Weeds of Melbourne – An Introduction

weed n.
Any herbaceous plant not valued for its usefulness or beauty, or regarded as a nuisance in the place where it is growing, esp. when hindering the growth of crops or other cultivated plants.

ruderal adj.
Of a plant: growing on waste ground or among rubbish, esp. as a pioneer; (also) designating a habitat of this type.

Rome, briefly

In the mid-1800s, the English botanist Richard Deakin carried out a survey of the plants growing within the ruins of the Colosseum in Rome. Deakin catalogued 420 species of plant, finding not only local native plants but a surprising number of species known from no other site in Europe at that time.

While not the first botanical inventory of the site, Deakin’s Flora of the Colosseum is remarkable for its breadth—this was the high point for species diversity recorded there, with the number of species having dwindled to 243 in a c.2000 survey after more than a century of intensive archaeological management.

The Colosseum in Rome, a Spring 2005 photograph by the Wikimedia Commons user Briséis.

But the Deakin survey, and those that came before and after it, are also notable for their recognition of the historical and social context of the ruin’s ruderal botany, stemming from centuries of use as a stockade, squatter’s garden, hideout and pilgrimage. While hosting many common spontaneous weeds of disturbed sites, the Colosseum also nurtured a variety of weeds specific to pasturage and cultivation, as well as beloved ornamental selections and rare endemics with no clear explanation of how they had come to grow there and nowhere else in the Roman region.

Also notable is how impossible it was and is to survey the botany of ruin without celebrating in word and illustration the physical context and expression of plants growing where they were not supposed to be. Consider for instance Deakin’s treatment of one of the first entries in the flora, for Star Anemone (Anemone hortensis): ‘It grows in various parts of the Colosseum, and there flowers freely, glowing in its bright colours like a joyous star upon the mouldering remains of past generations.’

This was not exactly the dispassionate voice expected of today’s consulting ecologists and of a generation of plant enthusiasts raised on the morality of native plants. Yes, it has more than a hint of the Victorian love of the morbid and of what was then a common eschatological anticipation for their own empire’s future ruin. But that poetry also stems from a practical recognition that ‘nature’ was not only somewhere out in the hinterland, and not only a collection of conserved fragments in remnant sites and their cultivated reexpression in revegetation projects. Our cities and settlements are not as ordered as we dream they are, they are built on the ruins and wastes of every previous failure, personal and collective.

Fennel (Foeniculum vulgare), a familiar introduced element of the Melbourne flora.

The weedy botany of Melbourne is the Colosseum flora writ large, across an entire metropolis erected in the blink of an eye, built predominantly out of pavements and walls of stone and clay, crumbling all but instantly into a state of perpetual ruin, and retaining nonetheless its position in global networks of trade and circulation. Where Deakin’s Roman flora archived the detritus of two millennia at the centre of the world, our city’s flora archives the destruction and interconnection of just two centuries at the edge of the Anglo-American empire.

To survey the flora of Melbourne today is to read the history and heritage of this arrival and occupation. In the botany of Melbourne, that is to say the botany of the built outpost, entrepôt and self-perpetuating engine of the Victorian colony, it is the weed plants, the opportunists, the discards and the infestations that form the primary text. This is a rich layer, barely assayed, and more than just the thin line of intervening cataclysm, even if we can (nor should) ever lose sight of this.

This flora, the weed flora, is Melbourne’s history seething and spasming into being, cyclical, constant in its description of annual and perennial pulses, but also an accumulation. It is a sum of faults, of mistaken notions, neglectful conduct, and intentional misdeeds; it is also a sum of aspirations, of creative impulses and hard labours, of works that at one time were viewed and felt as accomplishments. In short, it is a heritage.

1835 Plan of the Port Phillip District (John Helder Wedge, State Library of Victoria)

Melbourne sits within the Port Phillip and Westernport Catchment Management Authority (CMA), a region stretching from Ballan and Little River in the west, to Lancefield in the north, and the Yarra Ranges and Drouin in the east. While the catchment includes extensive rural and managed catchment areas, the sprawl of the metropolitan and its connective infrastructure is the dominant land use, land form, and ecological force of the region today. Indeed, while the metropolitan area is officially bounded at Frankston and Little River, in environmental history terms it arguably extends to Sorrento and Point Nepean on the south east side of Port Phillip Bay, with an outpost at Queenscliff and Point Lonsdale on the other side of the Rip, and extends out along the web of roads and railways that converge on Melbourne from the north and northwest.

Within that area, 1074 introduced, exotic plant species are recognised in the current, digital edition of the Flora of Victoria, the state’s botanical benchmark.

That figure catalogues every species of exotic or uncertain origin that has been recorded growing in naturalised or adventive conditions. It also includes Australian native species from Western Australia and the east coast which did not grow in Victoria prior to the colonial era but which have proven to be environmental weeds here. The figure includes some but not all of the species which are indigenous to other areas of Victoria but which have proven to be invasive within parts of the Port Phillip region.

The figure also does not include a number of species indigenous to the Melbourne area which have nonetheless proven themselves capable of growing as urban weeds. This channel does not treat ‘weed’ as a moral judgment or a prescribed management outcome, accepting the broadest definition of any plant growing where it is not valued or does not belong. If a cherished ornamental selection has been recognised as an environmental weed, we’ll acknowledge that, and we’ll also acknowledge the indigenous plants that prove themselves capable of colonising urban walls, pavements and flower pots.

Finally, that figure of 1074 introductions does not include the species that are today arriving as material contaminants or making the jump from garden gem to run amok as we speak. Botanical records are made after the fact; they require that someone tied into the herbarium system takes notice and makes a collection. 

All told, there may be 1300 species of plant growing as weeds in Melbourne today, approximately a third of the total number of plant species recorded in the region.

More than fifty other exotic species were recorded historically in naturalised circumstances within the metropolitan, but are treated today as ‘extinct’, having failed to persist or been forcibly extirpated. The pace and flux of disturbance and recruitment in the metropolitan creates incredible opportunities for arriving plants, but can also just as quickly close them. Coode Island and Studley Park, former hot spots for weed diversity, have been transformed by very different changing land uses such that neither supports the novel arrivals communities chronicled in past herbarium specimens. Today, material degradation of built structures creates unique niches for ferns and other petrophytes to exploit, but these opportunities may often be shortlived, with restoration or replacement of the decaying structures usually improving upon the past materials and methods.

For those who benefit from comparisons, the NSW eflora returns approximately 1050 introduced species for the Sydney metropolitan catchment, with similar caveats as to what may be missing from that number’s ‘weed census’.

Like Australia, much of North America has been recognised as a weed invasion ‘hotspot’ as a consequence of its similar colonial history and warm temperate position; the Jepson eflora for California returns approximately 1500 naturalised species for the bioregion that includes Los Angeles. And these numbers are notably higher than in major European or Asian centres; one academic census records just 478 naturalised species for the whole of Italy (Pysek et al 2017), though it must be recognised that treatments of European ‘native’ flora include hundreds of species that were relocated and introduced over several thousand years of accelerating agricultural and commercial exchanges and economic and ecological integration across the continent and with North Africa and Western and Central Asia.

Considering weed diversity

The weed diversity of Melbourne is particularly notable in the context of our damaged and increasingly urbanised region, in which much of the original floral diversity was suppressed and extirpated by the sudden and violent imposition of pastoral grazing from 1835 and by the environmental upheavals of extensive forestry and gold mining which followed.

Weeds here are the profusion of absence, the vital force emerging from the massive disordering produced by the European invasion, by the massacres, by the determination that this continent would be grazed by hooved mammals, extracted for the enrichment of capitalised classes, and surveyed and built upon to support the minor wealth and retirement schemes of many the rest of us participants. As a matter of course in contemporary Australia, we can find no shortage of mirrors for our damaged history and for today’s intransigent and accumulating political-economic-ecological crisis. But weeds are surely one of the more charismatic angles we might choose, all joyous stars on the mouldering remains.

Climate change, which has already brought to Victoria increased annual average temperatures, fewer frost days and general reductions in rainfall to much of the state in comparison to the gold rush period, can be expected to continue to open the door to pan-tropical and frost-tender invaders. At the same time, this will continue to close the door to other plants whose lifecycles rely upon winter chill or a moisture regime that is now receding in today’s prevailing norms. There is nothing set in stone about today’s Melbourne flora.

Neither is there any going back. The turn towards preferential cultivation of native plants and widespread pursuit of an ecologically-based revegetation of urban and rural landscapes is an important achievement of great influence and promise. However, even the greatest landcare successes are as much about creating a functional new ecology as reclaiming an ‘original’ native plant community out of this settlement’s history of massacre and destruction. And nowhere are our ecologists and volunteers so successful that there will ever not be weeds.

All of those initiatives, and the human and often voluntary labour they represent, which seek to regenerate something out of ruined and wasted places, are acts of gardening in the greatest ruined garden on Earth (to parallel the Bill Gammage title). Some technical institutions have recognised the necessity of gardening, shifting the bounds of play from weed eradication to weed management for instance, abandoning the impossible promises of past wars on thistles and prickly pears.

Within Melbourne’s gardens, reserves, infrastructure and wasted lands sprout all of the traumas and dislocations of the past, and so these will do from now to the end of recorded time, no matter the investment of labour and personal or collective suffering devoted to revegetation. The weeds, a thousand strong, are the newest layer atop the bay sludge and basalt spills that form the Melbourne geology, a seedbank that has made itself a permanent stratigraphic marker of the arrival. Just add light and water.

We are better to recognise the novel and cultivated nature of what we call ‘restoration’ than to maintain the illusions and the cultural sleight of hand embedded in that impulse to restore. Revegetation is not a restoration of the human values, relationships and physical management that ordered this place before the arrival. Neither is it the discontinuation of the forces that continue to erode the remnants and ruins of those old landscape systems. At their worst, the works that fall into the rubric of ‘restoration’ are a new coat of green paint; at their best, they are something new and viable, acknowledging that the past is the media out of which we sprout the future.

In all those futures, in the future, there will be weeds in Melbourne.