From “The Killing Plants” in Dangerous Garden: The Quest for Plants to Change Our Lives by David C. Stuart:
“Various tanacetums, including the herbaceous red or pink Tanacetum coccineum familiar in our gardens, yield [a] popular insecticide. T. cinerariafolium, in particular, is widely farmed for its pyrethrum. This substance rapidly kills aphids and caterpillars. It also kills beneficial arthropod predators such as lacewings, hoverflies and ladybird larvae. However, as it decays rapidly in air, vanishing within twelve hours, plants sprayed in the evening will not poison bees alighting on them the following morning. It is one of the oldest and safest insecticides available. The pyrethrum paralyses insects almost immediately, to spectacular effect. Many of the immobilized insects later recover.”
From The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth by Zoe Schlanger:
“All around me are complex adaptive systems. Each creature is folded into layers of interrelationship with surrounding creatures that cascade from the largest to the smallest scale. The plants with the soil, the soil with its microbes, the microbes with the plants, the plants with the fungi, the fungi with the soil. The plants with the animals that graze on them and pollinate them. The plants with each other. The whole beautiful mess defies categorization….
“Plants are the very definition of creative becoming: they are in constant motion, albeit slow motion, probing the air and soil in a relentless quest for a livable future….
“A life spent constantly growing yet rooted in a single spot comes with tremendous challenges. To meet them, plants have come up with some of the most creative methods for surviving of any living thing, us included. Many are so ingenious that they seem nearly impossible for an order of life weโve mostly relegated to the margins of our own lives, the decoration that frames the theatrics of being an animal.”
Hello!
This is the second of four posts with photos that I took in late November and the first two weeks of December, of Aster family members that I identified as Tanacetum coccineum, though they are similar in appearance to the Chrysanthemum genus plants Chrysanthemum ร morifolium and Chrysanthemum indicum. The first post is Technicolor Tanacetum (1 of 4).
With the photos in this second post, we visually transition from the solid-colored (mostly red) flowers to those where the petals show blended colors, which we can imagine helped give rise to one of the plant’s common names (that is still used today): Painted Daisy. With the last three photos in this post, we begin to see the expression of less blended, more distinctly different colors — which will be even more evident in the remaining series photos.

The first excerpt I included at the top of this post — from Dangerous Garden: The Quest for Plants to Change Our Lives by David C. Stuart — is only six sentences, but those rich sentences tell us a lot about the evolution of plant adaptation and survival strategies. If natural history was a cartoon, you might imagine a group of Tanacetum plants huddling together 300 million years ago to develop a plan for fending off aphid hordes, which — as any gardener who’s seen one of their invasions knows — can be very determined about chomping on a plant’s leaves and stems until there’s not a lot of leaf or stem left.
What more likely would have happened in real life rather than our cartoon, though, is that some Tanacetum plants — probably as a result of a chemical reaction to the aphid invaders — managed to produce a compound that paralyzed the aphids “to spectacular effect.” Those plants thrived better than species members that didn’t produce the compound, and passed the chemical formula to subsequent generations. That this chemical compound — which we humans call pyrethrin, a name that gave rise to the old plant genus name Pyrethrum — evolved over thousands of generations to target specific insect families and dissipate after a few hours are both fascinating elements of the story: the targeting and dissipation ensure that the plants wouldn’t prevent other, more desirable insects from fulfilling their roles as pollinators.
Should you happen to have some insecticide around, you can check the ingredients and find chemicals like bifenthrin or cypermethrin listed. These chemicals are synthetically produced but were modeled after pyrethrins. They were designed to emulate how Tanacetum pyrethrin targets specific insects while being more persistent than the natural compound — which dissipates within hours — so that the insecticide can keep an area clear of undesirable pests for days, weeks, or even months, demonstrating how humans adapted a plant’s evolved defense strategy and modified it to meet the needs of commercial pest control applications.
Thanks for reading and taking a look!


























































