Kerry Ferguson — Science + Art Research Series Essay | 2026
Citation: Ferguson, K. (2026). The Chemical Language of Plants: Signals, Scent and the Invisible Ecology of Information. Kerry Ferguson — Science + Art Research Series.
A landscape appears silent until we learn how much information is moving through it.
Plants release volatile compounds into the air. Roots alter the chemistry surrounding them. Flowers produce scents that influence pollinators. Damaged leaves change their emissions. Herbivores respond to plant chemistry. Predators can respond to compounds released by attacked plants. Microorganisms alter the chemical environment of roots and leaves.
None of this resembles conversation in the human sense. There are no sentences, intentions or shared symbolic languages. Yet information moves. One organism changes its chemistry. Another organism detects that change. A physiological or behavioural response follows. Science increasingly reveals ecological environments as networks of chemical information. For art, this creates an extraordinary challenge.
How do we represent a landscape whose most important relationships may be invisible?
What Does It Mean for a Plant to Signal?
The word signal has a specific biological meaning. A signal is not simply any chemical emitted by an organism. In evolutionary biology, signalling usually implies that information produced by one organism influences another and that the relationship has been shaped by selection.
A cue, by contrast, may contain useful information for another organism without having evolved specifically for communication.
The distinction matters because chemical ecology is filled with examples in which one organism exploits information unintentionally revealed by another.
The smell of a damaged leaf may reveal the presence of food to an herbivore. The same volatile mixture may alert a neighbouring plant to potential danger. A parasitoid may use the chemical signature to locate the herbivore responsible for the damage. The same molecules can therefore participate in several different relationships. Chemical information is contextual.
The Air Around a Plant Is Not Empty
Plants continually release volatile organic compounds, or VOCs. These molecules are sufficiently volatile to enter the surrounding atmosphere, where their concentration and composition can vary according to species, tissue, developmental stage and environmental conditions.
Some are released constitutively. Others increase dramatically after mechanical damage, herbivore attack or other forms of stress. A damaged plant can therefore occupy a chemically different atmosphere from an undamaged plant. The change may be invisible to us. To another organism it can be significant.
Research on herbivore-induced plant volatiles has demonstrated that airborne compounds can influence neighbouring plants, herbivores and natural enemies of those herbivores. In maize, for example, exposure to herbivore-associated volatile cues can prime defensive responses, enabling plants to react differently to subsequent attack. The atmosphere surrounding vegetation is therefore not chemically neutral.
Damage Has a Smell
Most people recognise the smell of freshly cut grass. That familiar scent is partly generated by compounds known as green leaf volatiles, released rapidly when plant tissues are damaged. Their presence provides an immediate example of how mechanical disruption changes plant chemistry. The scent is pleasant to many humans.
Biologically, however, it is associated with tissue injury. Recent experimental work has visualised how plants exposed to green leaf volatiles from damaged neighbours can produce rapid calcium signalling within their own tissues.
That is a remarkable transformation. An invisible airborne molecule released from one damaged plant becomes physiological information inside another. The scent of injury becomes part of a biological response.
The Signal Moves Through the Plant
Chemical signalling does not occur only between organisms. Plants must also coordinate information internally. A leaf attacked by an herbivore represents a local event, but an effective defence may require responses elsewhere in the plant.
Research has shown that volatile compounds can contribute to signalling between different parts of the same plant. This is particularly useful in plants whose architecture makes purely vascular signalling less direct. Air can therefore become an internal information pathway. A volatile emitted by one leaf may influence another leaf some distance away. The plant communicates partly through the space surrounding itself. The boundary between organism and atmosphere becomes less clear.
Priming Rather Than Immediate Defence
One of the most interesting aspects of plant chemical signalling is priming. A plant exposed to a warning cue does not necessarily activate its full defence system immediately. Instead, it may enter a physiological state in which it can respond more strongly or rapidly if attack subsequently occurs. This can be energetically advantageous. Defensive chemistry can be costly to manufacture and maintain. Preparing for danger without fully committing resources until danger arrives allows a plant to balance protection with growth.
Experiments with maize have demonstrated that airborne cues can prime plants for stronger production of defensive compounds following later herbivore attack. This introduces a concept familiar in human language but biologically quite different: information can change readiness without immediately changing behaviour.
Indole and a Specific Chemical Message
Plant volatile blends can contain dozens of compounds. This makes it difficult to determine whether biological responses depend on an entire mixture or particular components.
Research in maize has demonstrated that indole, one herbivore-induced volatile, can play a particularly important role in priming subsequent defensive volatile production.
Plants unable to produce normal herbivore-induced indole showed altered priming responses, while experimental exposure to indole restored aspects of that response.
This is significant because it begins to move the field beyond the idea that plants merely respond to a general smell of damage.
Individual molecules can carry distinct biological information. The chemical landscape has vocabulary. Again, the metaphor must remain careful. A molecule is not a word.
But different molecules can produce different effects.
Chemical Blends and Context
Individual compounds do not always operate independently. Plants frequently emit complex mixtures whose composition changes according to the type of damage or attacking organism.
Research comparing responses to different herbivores has shown that plants can release quantitatively and qualitatively different volatile profiles depending on the identity of the attacker. This provides richer information than simply indicating that “something has happened.” A chemical blend may carry information about the nature of the disturbance. This creates an intriguing parallel with colour. One pigment may provide information. A palette creates context. In chemical signalling, the relationships among compounds may matter as much as individual molecules. The message can exist in the mixture.
The Receiver Matters
Information has no biological significance without a receiver capable of detecting it.
Different organisms possess different sensory systems. A compound released by a flower may be highly significant to a pollinating insect while being irrelevant to another organism. A volatile associated with herbivore attack may influence a neighbouring plant but also attract predators or parasitoids.
Herbivores themselves can exploit plant volatiles to locate suitable hosts. The same chemical emission can therefore have multiple audiences. This means there is no single interpretation of a plant’s chemical output. Meaning emerges from the relationship between emitter, molecule, receiver and context. For art, this is particularly compelling. The work itself does not contain one fixed meaning independently of its audience either. Interpretation is relational.
The Enemy of My Enemy
One of the most extraordinary examples of plant chemical ecology is indirect defence.
A plant attacked by an herbivore may release volatile compounds that increase the likelihood that predators or parasitoids of that herbivore locate the damaged plant.
The plant does not physically attack its attacker. Its chemistry alters the behaviour of another organism. The defence exists through an ecological relationship. This is a fundamentally different model from a physical barrier such as a thorn.
The defensive system extends beyond the body of the plant.
It incorporates another species. From a design perspective, this suggests that function can exist in relationships between components rather than within an individual object.
A system can solve a problem indirectly.
Flowers Speak Chemically Too
Chemical signalling is not restricted to defence. Flowers release volatile compounds that contribute to pollinator attraction. The particular chemistry of floral scent can vary substantially among species and even across time. Some flowers release their strongest scents when their primary pollinators are active. The chemical signal therefore intersects with colour, shape, timing and reward. A flower is a multisensory structure.
We photograph the colour. Extract the fragrance. Draw the form. But within the plant they function together. The artistic lesson is important. Nature frequently communicates through multiple channels simultaneously.
Fruit, Seed and Dispersal
Plants also interact chemically with organisms involved in seed dispersal.
Ripening fruit changes in colour, texture, sugar concentration, acidity and aroma.
These transformations make the fruit increasingly attractive to organisms capable of dispersing its seeds.
The chemistry changes with developmental timing. A fruit that is chemically undesirable when seeds are immature can become attractive when dispersal becomes advantageous. The visible and chemical transformations are coordinated. Colour and scent become temporal signals. This reinforces a central idea of the series: botanical colour, scent and chemistry are processes rather than decorative attributes.
Below the Surface
The chemical landscape continues underground. Roots release compounds into the rhizosphere, the zone of soil directly influenced by root activity. These exudates can affect microbial communities, nutrient availability and interactions with neighbouring organisms. Roots encounter signals produced by microbes and other plants. Fungi produce their own volatile and soluble compounds. Much of this occurs beyond direct observation. The visible plant therefore depends upon an invisible chemical ecology beneath the soil. For an artist accustomed to surfaces, this introduces another layer. The most important structure may be hidden.
Mycorrhizal Networks and Caution
Popular descriptions sometimes portray mycorrhizal fungal networks connecting plants as a kind of underground internet. The metaphor is appealing. It can also exaggerate what the evidence demonstrates. Plants and fungi can exchange resources through mycorrhizal associations, and experimental research has investigated whether defence-related information can also move through shared fungal networks.
However, the ecological meaning, prevalence and direction of these exchanges can vary greatly among systems. A network should not automatically be described as cooperative communication.
Resources may move because of physiological gradients. Signals may benefit one participant more than another. Relationships can change according to environmental conditions. Science + Art should preserve this uncertainty. The network is more interesting when we do not force it into a social model.
Communication Without Intention
This leads to a difficult question. Does communication require intention? We often assume that it does. A speaker deliberately communicates information. Biological signalling does not necessarily operate this way. A flower need not “intend” to tell a pollinator where nectar is located. A damaged leaf need not “warn” a neighbouring plant consciously. Evolution can favour traits in which production and detection of signals influence survival or reproduction without conscious intention. This distinction allows us to discuss botanical communication without attributing a mental states to plants. The system can be sophisticated without being conscious.
Plants Also Eavesdrop
A receiver does not need to be the organism for which information was originally beneficial. Other organisms can intercept chemical signals.
Herbivores can exploit plant odours. Predators can exploit herbivore-induced plant volatiles. Neighbouring plants may respond to compounds released because of damage occurring elsewhere. In chemical ecology this is sometimes described metaphorically as eavesdropping. The metaphor is useful because it emphasises that information can be intercepted.
Once a molecule enters the environment, its effects are no longer controlled by the emitter. This makes chemical communication fundamentally ecological. Signals enter a community.
Public and Private Information
Some chemical information is broadly detectable. Other information may be more useful to particular species or organisms possessing specialised receptors. Researchers have described plant volatiles as carrying both “public” and “private” information.
A general damage-associated compound might indicate danger to many potential receivers. A more specific compound or mixture may reveal information relevant only to organisms with a particular ecological relationship.
This provides another artistic concept. Not every layer of an artwork needs to be equally accessible. Some structures can be immediately visible. Others may become meaningful only with additional knowledge. Understanding can operate at several levels.
Signal and Noise
Natural environments contain enormous chemical complexity. A plant must function within mixtures produced by itself, neighbouring plants, soil, microorganisms and atmospheric chemistry. How does a biologically meaningful signal remain detectable within this background? Part of the answer lies in sensitivity, concentration, timing, mixtures and context.
Environmental conditions also matter. Wind disperses volatiles. Temperature influences emission. Atmospheric oxidants can transform compounds. Distance reduces concentration. The message changes while moving through the environment. Communication therefore depends not only upon the emitter and receiver but upon the medium between them. The atmosphere participates.
When Pollution Changes the Message
This point has increasingly important environmental implications. Plant volatiles can react chemically after entering the atmosphere. Ozone and other pollutants may alter their concentration, lifetime or chemical identity. This can potentially interfere with ecological interactions involving insects and plants. The signal emitted is therefore not necessarily the signal received. The environment edits the message.
For art, the idea is powerful. Information is transformed by the medium through which it travels. Pigment changes according to fabric. Sound changes according to space. Light changes through atmosphere. Meaning is not merely transmitted. It is mediated.
Scent as Landscape
Landscape painting has traditionally been visual. Landscape experience is not. A eucalyptus woodland possesses a chemical character. A rainforest smells different after rain. Flowering plants can alter the scent of an environment seasonally. Dry vegetation produces another sensory landscape. These chemical qualities contribute strongly to memory and recognition of place. Yet scent is difficult to preserve visually.
Science allows us to identify compounds contributing to aroma. Art can ask how scent might be translated indirectly. Not by painting a smell, but through association, colour, layering, rhythm and memory. The invisible landscape can become visible without pretending to reproduce the chemistry itself.
Memory and Volatile Chemistry
Smell possesses an unusually powerful relationship with human memory. A botanical aroma can immediately evoke a place or time for example: rosemary, eucalyptus, clove, cut grass or wet earth. The scientific process identifies the volatile molecules involved, experience connects them with memory. The same chemical signal therefore exists in very different interpretive systems.
To an insect it may reveal food. To another plant it may indicate damage. To us it may evoke childhood. Chemical identity remains constant. Meaning changes with the receiver. This is one of the clearest examples of where science and art meet.
The Problem of Making the Invisible Visible
Visual art faces a basic difficulty with chemical signalling. The subject has no obvious visible form. A molecule can be represented through a chemical structure, but that structure is already a scientific abstraction. Simply reproducing molecular diagrams risks turning scientific information into decoration.
A stronger artistic approach begins with the behaviour of the signal. It moves, diffuses, changes concentration, crosses boundaries, triggers responses, disappears, combines with other signals and changes in the atmosphere. The artistic process can begin with these characteristics rather than with molecular shape.
Diffusion as Material Process
Dye moving through wet fibre offers one possible analogy. A concentrated colour enters a material, it spreads, its intensity decreases with distance, another colour intersects it and boundaries become uncertain. The result depends upon water, fibre, concentration and time.
The process is not chemically equivalent to volatile signalling. But materially it allows the artist to investigate similar concepts of movement and distribution. Science provides the question. Material provides another form through which to think about it.
Layering as Information
Chemical landscapes contain overlapping signals. An artistic surface can operate similarly. One printed layer can represent constitutive chemistry. A second can emerge after an imagined disturbance. A third can interrupt or obscure the first. Some areas can remain quiet. Others become dense. The final image records a sequence rather than a single event. This approach avoids literal illustration. The work becomes a visual model of changing information density.
Colour as Concentration
Scientific graphs often represent concentration numerically. Art can represent concentration spatially. A dense pigment can suggest high signal intensity. Gradual fading can suggest dispersal. Repeated marks can suggest accumulation. Sudden colour changes can represent a threshold response. These interpretations remain metaphorical. Their value lies not in pretending to display actual chemical measurements, but in allowing scientific concepts to influence composition. Data becomes a way of thinking about visual relationships.
Embroidery as Network
Thread provides another useful material language. A stitched line can connect separate areas of a surface. Several lines can converge. Others can terminate. Knots can create sites of intensity. Threads can pass beneath the fabric and reappear elsewhere. This makes embroidery particularly suitable for exploring networks whose connections are partly visible and partly hidden. The surface can become analogous to an ecological information system without becoming a literal diagram of one. The stitch is both structure and trace.
Responsive Materials
Chemical signalling also raises the possibility of artworks that physically respond to their environments. Pigments can change according to pH. Some materials respond to ultraviolet light. Metals oxidise. Hygroscopic materials respond to humidity. Thermochromic systems change with temperature. Living or biologically derived materials introduce still greater possibilities.
A Science + Art practice does not need to use sophisticated responsive materials merely for novelty. But when the subject is environmental sensing, a material that itself responds can make the conceptual relationship considerably stronger. The work behaves rather than merely represents behaviour.
From Perfume to Ecology
Fragrance industries isolate and combine botanical aromatic compounds primarily according to human sensory preferences. Chemical ecology reveals another history behind those aromas. Linalool, limonene, eugenol and other familiar volatile compounds participate in biological systems before entering bottles, foods or formulations. This changes how we might think about botanical fragrance. Perfume is not merely extracted beauty. It is chemistry removed from ecological context and recomposed for another sensory system: ours. That transformation is culturally fascinating. A molecule crosses from plant ecology into design aesthetics.
Essential Oils as Concentrated Signals
Essential oils present an especially interesting case. They contain concentrated mixtures of volatile plant compounds. Industrial extraction removes these molecules from the biological tissues and structures in which they originally existed. The resulting oil can possess aroma far more intense than the living plant normally releases into its environment. The signal has become an ingredient. It can then be encapsulated, formulated, diluted or combined with other materials. The commercial process transforms ecological chemistry into technological chemistry. Science + Art can ask what is changed when signals become products.
The Ethics of Anthropomorphism
Plant communication attracts public interest partly because it invites analogy.
Plants warn each other. Trees talk. Forests share information. These phrases are memorable. They can also obscure the science. Plant ecological interactions are compelling precisely because they demonstrate different ways biological systems process information. Science + Art should therefore use metaphor transparently.
The phrase chemical language belongs in the title because it helps us recognise an invisible information system. The essay should simultaneously acknowledge that this is metaphor rather than evidence of syntax, intention or human-like thought. Scientific accuracy makes the artistic question stronger, not weaker.
Listening Differently
We traditionally describe attentive engagement with nature as looking and listening.
Chemical ecology suggests another form of attention. We can learn to recognise that processes exist beyond our sensory range. We cannot smell every volatile compound.
We cannot detect root exudates directly. We cannot perceive plant calcium waves without instrumentation. Yet those phenomena form part of the landscape. Scientific instruments extend perception. They allow us to “listen” chemically. Art can then interpret what has become perceptible. The process moves from environment to instrument to knowledge to material.
Science Changes the Landscape
Once chemical signalling is understood, a garden looks different. A flower is not simply coloured. It is emitting information. A damaged leaf is not simply broken. Its chemistry has changed. The air between plants is not empty. The soil surrounding roots is not inert. A pollinator is not merely visiting a flower. It is participating in a sensory relationship. Scientific knowledge adds invisible layers to ordinary experience. This is perhaps one of the most important purposes of Science + Art. It enables knowledge to change perception.
A Framework for Artistic Research into Chemical Signalling
A rigorous Science + Art project can begin by identifying a documented signalling relationship. The biological evidence should first be understood clearly. Which organism emits the compound? Under what conditions? Which organisms detect it? What measurable response follows? How certain is the interpretation? Only then should artistic translation begin. The artwork might focus on diffusion, concentration, interception, network, transformation or response. The scientific phenomenon provides the conceptual framework. The material process provides the artistic language. The final work should not claim to demonstrate the biological process. It should allow the viewer to encounter its ideas differently.
From Chemical Language to Biomimicry
Chemical signalling also creates a bridge to biomimicry. Living systems detect environmental information, respond selectively and frequently operate with extraordinary sensitivity.
Technology increasingly seeks materials and systems capable of sensing and responding to environmental conditions. The value of biomimicry, however, is not in copying a leaf or reproducing a chemical signal literally. It lies in asking how biological strategies might reveal new ways of solving human problems.
A dedicated essay in this series will explore that transition in greater depth. The chemical language of plants provides one of its strongest starting points.
Conclusion
A landscape contains more information than we can perceive directly. Plants release volatile compounds. Roots modify their chemical environments. Flowers attract pollinators through combinations of scent, colour and reward. Damaged tissues alter emissions. Neighbouring plants can respond to airborne cues. Predators can locate herbivores through plant-associated chemical information. Scientific experiments have demonstrated that these interactions are not merely poetic interpretations. Herbivore-associated volatiles can prime neighbouring plants for later defence; individual compounds can participate in that priming; and plants can rapidly transduce exposure to damage-associated volatiles into intracellular calcium signals.
Yet describing this as a language remains a metaphor. Plants do not compose sentences. They do not need to understand meaning consciously. They do something biologically different and perhaps more interesting. They exist within systems in which molecules carry information between tissues, organisms and environments. The message can be emitted unintentionally. It can be intercepted. It can benefit another species. It can be altered by atmosphere. Its meaning changes according to the receiver.
Science reveals these relationships by separating compounds, measuring responses and testing mechanisms. Art gives us another way to encounter them. A diffusing pigment can make movement visible. A layered textile can suggest overlapping information. A stitched network can reveal connections that disappear beneath a surface. Responsive materials can physically change with their environment. None of these becomes plant science. They remain artistic investigations. Their value lies in allowing the scientific knowledge to alter the way we look.
Once we understand that plants occupy a chemical landscape as well as a visible one, the space between them changes. The air is no longer empty. The soil is no longer silent. The flower is no longer merely beautiful. And scent is no longer simply scent. It is evidence that the living world is continually exchanging information in ways that existed long before we began trying to listen.
Research Context
The Chemical Language of Plants forms part of Kerry Ferguson’s Science + Art Research Series and continues the research themes established in The Intelligence of Plants and Plants as Chemical Engineers.
The essay examines scientific research into volatile organic compounds, herbivore-induced signalling, plant defence priming, ecological interactions and plant sensory responses.
The artistic research considers how invisible processes including diffusion, signalling, interception, concentration and response can be translated into material processes without presenting artistic metaphor as scientific evidence.
The work sits independently between Botanical Innovations’ research into botanical chemistry and essential oils and Dangerous Beauty’s exploration of pattern, material, landscape and natural systems.
Selected References
- Heil, M. & Silva Bueno, J.C. (2007). Within-plant signaling by volatiles leads to induction and priming of an indirect plant defense in nature. Proceedings of the National Academy of Sciences, 104, 5467–5472.
- Engelberth, J., Alborn, H.T., Schmelz, E.A. & Tumlinson, J.H. (2004). Airborne signals prime plants against insect herbivore attack. Proceedings of the National Academy of Sciences, 101, 1781–1785.
- Erb, M. et al. (2015). Indole is an essential herbivore-induced volatile priming signal in maize. Nature Communications, 6, 6273.
- Aratani, Y. et al. (2023). Green leaf volatile sensory calcium transduction in Arabidopsis. Nature Communications, 14.
- Heil, M. & Karban, R. (2010). Explaining evolution of plant communication by airborne signals. Trends in Ecology & Evolution, 25, 137–144.
- Gershenzon, J. (2007). Plant volatiles carry both public and private messages. Proceedings of the National Academy of Sciences, 104.
- Baldwin, I.T. & Schultz, J.C. (1983). Rapid changes in tree leaf chemistry induced by damage: Evidence for communication between plants. Science, 221, 277–279.
- Wenig, M. et al. (2019). Systemic acquired resistance networks amplify airborne defense cues. Nature Communications, 10.
- Mann, L. et al. (2021). A comparative study of plant volatiles induced by insect and gastropod herbivory. Scientific Reports, 11.
- Zhang, P.J. et al. (2019). Airborne host-plant manipulation by whiteflies via an inducible blend of plant volatiles. Proceedings of the National Academy of Sciences, 116.
- Zu, P. et al. (2020). Information arms race explains plant–herbivore chemical communication in ecological communities. Science, 368.
- Sakurai, Y. et al. (2024). Plant–plant communication in Camellia japonica and related species. Scientific Reports.
- Li, T. et al. (2016). Atmospheric transformation of plant volatiles disrupts host plant finding. Scientific Reports, 6.
- Karban, R. (2015). Plant Sensing and Communication. University of Chicago Press.
- Taiz, L. et al. Plant Physiology and Development. Oxford University Press.