Invasive Pigments is an ongoing project focused on the migration and proliferation of certain plants in tandem with dense human populations. I gather unintentional plants (also known as “weeds”) living in my neighborhood and mine them for pigments, which are used to construct map-like portraits, diagrams and field guides. The results can take a range of forms, from drawings, videos and gardening experiments to web guides and xerox handouts for walking tours.

The drawings and maps detail species’ points of origin and spread through contact with humans, while the pigment diagrams demonstrate connections, both metaphoric and physical, between plants, pigments and urban habitats. The workshops and walks focus on plant identification, evolutionary adaptation to life in cities, and of course making and using paint.

Through the gathering, cultivating and processing wild and feral species on an intimate scale, the project encourages dialogue around the wider implications of labeling species as “alien”, “exotic” or “invasive” and allows project participants to experience their urban habitat in new ways. Blog posts about the project are here, and references and press can be found at the bottom of this page.


Above: color samples made of gum arabic and pigments derived from leaves, stems, roots, blossoms and fruits of local spontaneous plants (from Morrow’s honeysuckle to ailanthus to garlic mustard). The video below documents of the process of assembling the palette, from gathering plants in Bushwick, Brooklyn to painting with the resulting watercolor paint. Scroll down for a selection of the resulting paintings.

Invasive Pigments was on view at the Center for Strategic Art and Agriculture from November 7th 2014 – January 15th 2015. The CSAA also hosted the first Invasive Pigments Garden, documented below as it evolved from bare earth in March of 2014 to a towering canopy in the fall. There is a video about that process here: Spring to Senescence.





Above: Invasive Pigments Color Wheel, 2013
(thanks to Flickr users clspeace, treegrow, esagor, Esteve.Conaway and klm185 who provided Creative Commons licensed photos for this piece!)


Above: Asiatic Dayflower: Wildflower/Superweed, 2014


Above: Columbian-Asiatic Exchange (Pokeweed and Asiatic Dayflower), 2013. Pokeweed (Phytolacca Americana) is native to south eastern North America, where it was used as a dye and an ink by Native Americans and early European colonists. It has been spreading steadily throughout the United States and Europe over the past 400 years. It was probably introduced to Europe and Africa during the Columbian Exchange for its dye properties and perhaps as an ornamental. Asiatic Dayflower was introduced to the West from China further into the Columbian Exchange. The earliest record of its existence in the United States is in a botanical collection where it is dated 1898. It may also have been introduced as an ornamental, and has recently begun appearing in crops of Roundup Ready soy beans and corn. It seems to exhibit a resistance to glyphosate, the main pesticide in the herbicide Roundup.

Irons_Ellie_Celastrus orbiculatus_bittersweet

Above: Oriental Bittersweet (Celastrus orbiculatus) is native to northeastern Asia and was imported to the United States in 1860 as an ornamental. It was later used to stabilize soil along roadsides and highway embankments, where it escaped cultivation and naturalized, spreading rapidly through the eastern states over the past 50 years, radiating out from its highest population density just south of Asheville, North Carolina. Its vine-like structure and climbing tendencies allow it to shade-out and/or smother other plants and trees, and it creates direct competition for the native American bittersweet.

Above: Columbian/Eurasian Exchange (Black Cherry/Garlic Mustard), 2013

Black cherry (Prunus serotina) is native to the eastern United States and South Eastern Canada. However, it has become invasive in several northern and central European countries where it reduces the biodiversity of native woodland assemblages and impedes forest growth. It was among the first to American trees to be introduced as an ornamental in European gardens (arriving in England as early as 1629) and has successfully naturalized in a range of temperate climates.

Garlic mustard (Alliaria petiolata) is native to Eurasia. Since Europeans arrived in the northeastern Americas, it has spread throughout much of the northeast and mid-west United States and Canada. Young shoots were eaten by peasants in Europe, so its introduction may have been purposeful. It thrives in forested communities and edge habitats. With no known natural enemies here (deer avoid it), it has the potential to spread broadly, specifically into areas disturbed by human activity. There are risks of further introduction to similar climatic zones in other continents.

Above: Asiatic Dayflower (C. communis), 2012

Above: Barberry is a popular garden ornamental that came to the north eastern United States from the mountains of Japan, via St. Petersburg. It is now naturalized across much of the East Coast, where it is avoided by deer and thus flourishes as an understory plant.

Above, an experiment with local and upstate algae, including didymo, a microscopic invasive diatom.


Many of the facts stated above are drawn from Peter Del Tredici’s excellent book Wild Urban Plants of the Northeast: A Field Guide. Other useful resources for information on non-native and invasive plants include: