When Banu Subramaniam thinks about whether plants should be renamed so as not to honour white supremacist colonialists – Cecil Rhodes, for example, is commemorated in the names of 126 plant species – she contrasts it with how, for so many years in our patriarchal system, women were expected to change theirs. “That wasn’t considered complicated… and yet those in power give any number of reasons why this is,” says the professor of women’s and gender studies at Wellesley College, outside Boston, Massachusetts. Subramaniam is the author of the provocative new book, Botany of Empire. The book challenges plant science to better see the ways in which it has been profoundly shaped by European colonialism and how imperial attitudes, theories and practices endure. Colonialism and colonial logic remains “sedimented at every level”, argues Subramaniam, who also looks at what a more widespread and serious effort to “decolonise” might look like, even if such a project is never-ending. The book focuses on three subfields: taxonomy, plant reproductive biology and invasion biology (the science of the spread of introduced species). Subramaniam grew up in postcolonial India where she received a “colonial-style biological education”. She gained her PhD in evolutionary biology in the US before finding feminist science and technology studies. She describes herself as an interdisciplinary scholar: “The sciences see me as having left science… I don’t,” she says. The book enters the fray at a contentious moment. It is the International Botanical Congress (IBC) in Madrid in July and the so-called Nomenclature Section, responsible for the International Code that governs the scientific naming of plants, will be meeting to discuss and decide on a number of amendments that taxonomists have proposed since it last met seven years ago. Included is whether a mechanism should be added to the code so plant names that are regarded as culturally offensive or inappropriate can be rejected. If it passes the preliminary voting stage, it will be over to about 200 taxonomists who have individual votes along with the power to cast secret votes for their institutions. Think of how useful plant taxonomy was to the colonial project, says Subramaniam. The impulse to create a universal plant nomenclature was necessary for empire because it gave it a way of identifying and mapping its spoils. “[The colonialists] wanted to know: ‘Was the nutmeg plant here the same as this plant there?’” she says. In addition to the way colonialists are celebrated in plant names, colonialism endures, including in how reference specimens for species, selected when they are named, are often still housed in western herbaria, which still control botanical norms; in how “parachute science”, where western botanists pop into formerly colonised countries and then return home to process the specimens and publish, lives on; and even in the way our nomenclature persists (the Latin-based binomial system of naming plants with the genus followed by the species, developed by Swedish biologist Carl Linnaeus in the 1700s, won out). Today we demonise non-native plants as evil and undesirable. Subramaniam worries that this is helping to fuel xenophobia In the case of plant reproduction, Subramaniam draws on the work of historians of science who show how European colonial sexual norms based around heterosexual romance were transposed on to plants by Linnaeus. She argues that, as a result, our vocabulary and how we think about the way plants reproduce today “relies obsessively” on binary categories of male/female with their limited possibilities. Into this “impoverished” framework we try to shoehorn a breathtaking array of plant reproductive arrangements. More than 85% of flowering plants end up classified as “bisexual” or “hermaphrodite”, because the flowers have male and female parts; and that’s not to mention all the “asexual” ways flowering plants can propagate such as through roots, stems, leaves and buds. “There are more exceptions than rules,” says Subramaniam. “Plants do such interesting things… if we had better ways to describe them that aren’t based around human reproduction, it might open up other ways to study them.” (Subramaniam has published suggestions of new terminology and vocabulary.) Meanwhile, when it comes to invasion biology, the good native/bad foreigner binary that has become so pervasive in how most people think about plants’ place in the world is deeply ironic. We seem to have forgotten that it was European colonialism that ushered in the “massive and grand reshuffling of global biota” that we see before us. That they are here, for good or bad, is a legacy of colonial botany. And most of our agricultural species are foreign, too, though we don’t hate them on our dinner plates. Yet today we demonise non-native plants as evil and undesirable. Subramaniam worries this is helping to fuel xenophobia and giving us poor approaches to species conservation and management. Blame the plant and attention flips to violent eradication, which rarely works. Meanwhile the real problem, landscapes disturbed through overdevelopment (for it is often here that introduced species find their chance), takes a back seat. Former colonies’ promoting and protecting of native plants – essentially trying to return the environment to some kind of idyllic past state – while simultaneously showing so little regard for the Indigenous people who co-evolved with those flora and fauna, is a continuation of a colonial settler logic, suggests Subramaniam. “We need other logics for our approach to nature… not ideological litmus tests,” she says. For Sandra Knapp, a taxonomist at the Natural History Museum and past president of the UK’s Linnean Society, the book provides an interesting perspective on botany but she questions some of Subramaniam’s characterisations. While colonialists’ names do persist in plant names, it is a stretch to say the field is “celebrating” those people; big herbaria aren’t just confined to the global north, although there are more there; and “parachute science” is diminishing. One of the reasons botany used male and female when talking about plants’ pollen and ovule-bearing organs is because it made common understanding easier. “As plant scientists discover more about plant reproductive biology, they realise it kind of defies categorisation,” says Knapp, referring to a recent discovery about the sexual fluidity of an Australian bush tomato. But, chiefly, Knapp questions the book’s starting point: that botany has its head in the sand over its colonial past. While botany isn’t a monolith, from Knapp’s perspective, the journey is under way: the field is actively engaged with thinking about and coming to terms with its past, as well as how it might create a more inclusive future. “There’s a blossoming of this discussion throughout botany now,” says Knapp. “It might not be the conversation [Subramaniam] thinks there should be, but that’s all the more reason to keep it going.” Knapp points to a wealth of projects taking place at institutional and grassroots levels to amplify different voices: the Linnean Society’s addition to its library of portraits celebrating its first female fellows; a recent project by botanists to relay untold stories of individuals who collected and studied plants but who have been excluded from historical accounts; and work she has been undertaking with colleagues to produce a dataset of plant genera named after women. There are also more proposals to change the code to make things more inclusive than just the plant names suggestion. They include requiring, where possible, the herbarium where a new species reference specimen is deposited to be within its native geographical distribution; and rejigging the code’s voting system to one vote per institution to establish a fairer global distribution of institutional votes (currently larger institutions – which skew to the global north – have more votes so retain more influence). Another naming proposal is to permanently and retroactively eliminate the use of root words in plants’ second names that link to a particular racial slur. There are “pockets” of effort, acknowledges Subramanian, though whether the code will change in these ways remains to be seen. And, from a decolonisation perspective, there are lots of questions: who will be on the committee that deems what names are culturally offensive or inappropriate? What will the names be replaced with? “There are no easy projects of decolonisation… and it’s going to take a long time to figure out,” Subramanian says, adding that the main project must be one of botany unearthing, teaching and continually reminding itself of its history. Maybe it’s time to bring this below-the-radar subject into the open Ken Thompson, ecologist Meanwhile, Subramaniam’s critique of invasion biology hits the mark for some such as Ken Thompson, a retired ecologist from Sheffield University and author of the 2014 book Where Do Camels Belong? It isn’t the mainstream view, notes Thompson, but that our vilification of non-native species is misplaced is something he too has long argued, to plenty of criticism. “Maybe it’s time to bring this below-the-radar subject into the open,” he says. Not least, global heating means species have to move and we may need to welcome new ones. As Thompson sees things, focusing more on the function of plants rather than their origin is a better approach. Yet for Daniel Simberloff, a professor of ecology and evolutionary biology at the University of Tennessee, Subramaniam’s arguments, which he has encountered before, remain tortuous and unconvincing, and lack evidence. Not only does she “almost completely” ignore the impacts of many non-native species, but there is also scant proof that judgments about the aesthetics of non-native plants transfer to xenophobia. And approaches to restoration, which involve removing non-native species, aren’t so much about trying to return land to some unspoilt past but giving degraded ecosystems a fighting chance to recover. There are plenty of examples where campaigns to eradicate invasive non-native species have worked, he notes. Responding to a recent study that found invasion biology research negatively frames non-native species, regardless of whether they cause harm, Simberloff and others in the field point out that the accumulating evidence is that substantial numbers of non-native species are going on to have a harmful impact. The rule of thumb used in the past – that only 1% of non-native species can be expected to become pests – is a “highly misleading low estimate” (though a new estimate is hard to give). Given that it isn’t always clear which non-native populations can “irrupt into invasion problems”, a precautionary principle, even if they seem benign, is prudent, they argue. They also point to a “formidable international scientific consensus” that non-native species pose threats, citing a sobering Invasive Alien Species Assessment published last September by an intergovernmental body representing 143 member countries. Subramaniam stresses it is not that non-native species can’t, in some cases, go on to be real concerns. She cites kudzu in the US, water hyacinth in India, and itadori [Japanese knotweed] in the UK. But the problem is us, and we should take responsibility: most are “invited invasions” and that they may become overrepresented is a symptom of our destructive ecological approach. “Instead of just blaming the plant and telling the story of the invading foreigners coming to take over, let’s retell it and hold human hubris to account,” she says. Her takeaway message when it comes to plant science: “Botany, like everything, is political. Question received wisdom.” The Botany of Empire by Banu Subramaniam is published by University of Washington Press (£25.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply