As any environmental historian will attest, a ‘weed’ is a social construct, not a biological one. Whether or not a plant is classified as a weed or, more formally, an invasive species, is historically and geographically contingent, wholly dependent on the value of its ecological behavior within a human-environment interaction. Uncovering the decades-long or even centuries-long process by which a plant goes from being a welcome transplant to an invasive threat exposes as much about the political, cultural, and economic transformations of human societies that interact with that plant as it does about the plant's actual behavior. Nowhere is this more evident than in Jeremiah Kitunda's A History of the Water Hyacinth in Africa: The Flower of Life and Death from 1800 to the Present, a sweeping epic that traces the introduction and spread of the South American Eichhornia crassipes.

In this book, Kitunda skillfully demonstrates the deep connection between the ecological history of this aquatic plant and the history of the African continent from the early eighteenth century to the present day. Water hyacinth is an aesthetically beautiful plant that chokes river systems quite literally from the Cape to Cairo, challenging farmers, fishers, engineers, and governments across Africa. Kitunda argues that the story of the water hyacinth in Africa, from an ornamental exotic to a dangerous alien interloper, or, as he puts it, ‘from Beauty to Beast’, reveals important aspects of Africa's encounter with Western imperialism, biota, science, and technology, as well as its postcolonial engagement with the global economy, urbanization, agricultural development, and tourism over the last two hundred years. Hyacinth, Kitunda claims, provides a botanical map of the history of African modernity.

This analysis offers a critique of Alfred Crosby's enduring Ecological Imperialism thesis(1986), which depicts introduced plants as handmaidens of successful imperial domination (though it is important to note that Africa, pushed aside as geologically ‘old world’, was always the elephant in the room for Crosby). Concurring with a growing literature on colonial invasion ecologies led by William Beinart, Karen Middleton, Lance van Sittert, and Simon Pooley, Kitunda shows how introduced plants like water hyacinth were not always allies of imperialists, but often rebelled against and even weakened colonial empires in Africa. Colonial development projects reshaped environments and unwittingly produced aquatic ecosystems that were highly vulnerable to invasive species. Even though hyacinth had been growing in multiple sites on the African continent from the early nineteenth century, it was not until the end of the century (or later in some locales) that officials, farmers, and fishers became fully aware of the plant's potential threat to both local and imperial economies and began to characterize it as a noxious weed. Precolonial waterways, even in Africa's most active agricultural zones, were low in nitrogen and phosphorus, which aquatic plants need to grow. However, as waterbodies became adulterated with nitrogen and phosphorous-rich agricultural, industrial, and urban waste in the colonial era (1880s–1970s), hyacinth thrived on this new food source. Its rapid overgrowth in wetlands, lakes, and rivers threatened fish, wildlife, and livestock populations — and the humans who relied upon them. It also blocked irrigation canals, interfered with navigability of waterways, and augmented malaria and bilharzia vectors. Development, Kitunda contends, begot hyacinth, and because development crossed the colonial-independence frontier, new postcolonial states inherited these problematic ecologies and saw them worsen, particularly with the construction of large-scale irrigation and hydroelectric dam projects.

The success of this work rests upon its innovative methodology and its geographic scope. As with many histories of invasive ecologies, significant documentary evidence of an invasive plant's ecology only emerges once it has been deemed a nuisance. Between when a colonial botanic garden keeper records its introduction into a pot or pond in the early nineteenth century and when a colonial agricultural department compiles a report on the detrimental effects of its overgrowth in irrigation systems, or a fishing community begins to take note of declining hauls a century later, there are scant traces of water hyacinth in traditional archives. Kitunda works around this problem by conducting a thorough search of herbarium specimens collected across Africa in the colonial era and preserved, by date, in African, European, and American natural history museums and botanic gardens. These sources help to create a compelling narrative and visual record of water hyacinth's historical distribution. In individual chapters, Kitunda moves methodically through the continent's major river systems (the Nile, Zambezi, Congo, and Niger River basins and various Indian Ocean basins) to highlight regional variances in the introduction, spread, and management of water hyacinth. Kitunda's command of such a wide geography is both impressive and essential to understanding the continental scope of his argument, though a more robust probing of the comparative social and economic dimensions of the regional analyses would have made the flow of the chapters less encyclopedic. How, for example, did government responses to the hyacinth threat differ in colonial economies based on large-scale white settler capitalism versus those economies reliant on small-scale African production?

The transregional analysis is strongest when Kitunda examines hyacinth management strategies, particularly how states instituted and continue to negotiate contested eradication efforts, biological controls, and utilization programs. In his policy-oriented conclusion, Kitunda explores the new livelihoods created by eradication and utilization programs, new ecological problems generated by biological controls, and the continuing need for local and national governments (and historians) to appreciate and respond to the complexities of development and invasion ecology.