AGENDA
been better visibility for traffic and zero maintenance.
Interestingly, the latter has not been the case.
The artificial turf is permeable and, as such, it
now supports the following annual plants that are
considered weeds: Conyza bonariensis (fleabane),
Sonchus oleraceus (milk thistle), and an understorey
of Hypochaeris radicata (cat’s-ear). This meadow of
Asteraceae (daisy family plants) is virtually impossi-
ble to be rid of as their seeds are wind-dispersed; the
local council now sprays and slashes the median strip
regularly and the artificial turf is almost invisible.
The irony of this situation is that the removal of
a supposed weed (agapanthus) has resulted in a suite
of weeds.
The maintenance of this landscape has greatly
increased since the placement of the turf, yet the
outcome is much poorer. This is not an isolated case.
We need to start thinking about how to work with
new urban ecologies that include what may be consid-
ered weed species, especially in hostile environments
like streetscapes. We need to move away from the
Georges-Eugène Haussmann model of the monocul-
tural avenue street planting and embrace a more
responsive approach to planting design.
Species selection for street plantings should
take into account the aspect, the local geology and the
enhancement/screening of views. Working with the
recognized tropes of copses, drifts and clusters offers
possibilities and opportunities as designers. Rather
than pouring resources into trying to maintain static
landscapes, we could redirect resources into manag-
ing successional landscapes that have a level of
spontaneity and delight.
Ulmus minor “Atinia” (elm) was planted exten-
sively in Melbourne in the nineteenth century – it is
almost extinct in its natural habitat in Europe and yet
it thrives in Melbourne, often becoming “weedy.”
This tree will form a copse very quickly via root
suckers. On High Street, at the entrance to Northcote,
there is an avenue of senescent elms. Photographs
from the nineteenth century show a fantastic array of
gaudy exotica with an understorey of Agaves,
Pelargoniums and Gazanias. For the past ten years
the understorey has been a thick layer of woody
mulch often made blue by the indicator dye used in
glyphosate, which is used to kill the elm suckers.
If the suckers were allowed to grow, a beautiful copse
of elms would manifest in a few years; instead, the
avenue has recently been mass-planted with cultivars
of Western Australian desert shrubs. It will be inter-
esting to see how these plants compete with the elm
suckers and the constant poison drift.
There is anecdotal evidence that kangaroos and
cockatoos often dig up or ringbark trees and other
vegetation planted by humans but do not touch self-
sown plants of the exact same species. Perhaps
subconsciously, vandals who snap and rip out newly
planted trees are acting on the same instinct.
Establishing vegetation in the hostile environment
of a streetscape is difficult and expensive, but there
is a whole suite of plant species that would happily
self-sow and green our streets of their own volition,
most of them far more suited to our changing environ-
ment than the species we select.
The more rambunctious a weed is, the more
value it has in hostile urban environments – as long
as it can be contained within that environment.
Alianthus altissima (tree of heaven) is the “urban
wonder tree.” There is a copse of it above the Banana
Alley Vaults, between Flinders Street and the Yarra
River, growing in gravel that is about 300 millimetres
deep. The trees grow in the most hostile environ-
ments imaginable and yet they thrive. Alianthus can
thrive in extreme air pollution and can cope with
compaction, salinity, heavy metal contamination and
extreme temperatures. It already exists throughout
inner-city Melbourne, so why not embrace it and use
it to full advantage?
As Australian cities face rapid development in
response to population increase and a more extreme
climate, we need to examine how we can use so-called
weed species to green and cool our urban streets-
capes. We need to radically increase the amount of
vegetation in our cities if they are to remain liveable.
To destroy healthy, thriving vegetation just because it
is considered a weed is questionable. To replace weed
species with plastic grass is an ill-conceived act of
environmental vandalism. It’s time to tell the Emperor
that his new clothes are a skirt of fake grass dripping
in glyphosate.“To replace weed species with
plastic grass is an ill-conceived act
of environmental vandalism.”2LANDSCAPE ARCHITECTURE AUSTRALIA MAY 2017 27