Tag: tanacetum

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 we’ve 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 × 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!

From Chrysanthemums (Botanical) by Twigs Way:

“[For] a flower so beneficial to mind and body and so universally beloved, the genus Chrysanthemum into which all the garden chrysanthemums belong is now a much reduced one. Recent advances in the phylogenetics of the plant world have reduced the chrysanthemum to a mere thirty familiar species, ousting the likes of feverfew, ox-eye daisies, marguerites and Shasta daisies, which were once proud members of the chrysanthemum fold, and scattering them instead among the Leucanthemum, Argyranthemum, Glebionis, and the Tanacetum….

“The botanical history of the chrysanthemums is indeed a complex one, made more so by the intense hybridization that has been encouraged over the history of cultivation and a tendency to polyploidy (having more than one set of chromosomes), so that despite the rapidly decreasing number of species, there are literally thousands of cultivars, hybrids and varieties. Thus the chrysanthemum presents an immediate contradiction in being both a shrunken genus and a rapidly expanding one, albeit expanding on the basis of an almost incestuous inclination. A recent writer on the chrysanthemum was driven to state that the number of cultivars ‘is very unclear’ and blamed multiple cultivars for a tendency to introduce a ‘wild card’ every so often, seized upon by breeders to try and improve hardiness or encourage a distinctive petal shape….

“Despite this proliferation, almost all varieties of the so-called Chinese and Japanese chrysanthemum beloved of the florist and show breeder are blended hybrids or other forms derived from Chrysanthemum x morifolium and Chrysanthemum indicum, both natives of eastern Asia… [although] it was not until they had crossed continents with the aid of Victorian and Edwardian plant hunters that they were actually introduced to each other….”

Hello!

This is the first of four posts with photos that I took in late November and the first two weeks of December, of Aster family members that had survived an early winter freeze at Oakland Cemetery, and were none the worse for wear.

As one does, I used Plantnet to identify these plants, and it came back with a consistent identification that they are most likely Tanacetum coccineum, or — a slimmer possibility — that they are either Chrysanthemum × morifolium or Chrysanthemum indicum.

This specific mixed result is more interesting than it is confusing, and possibly more interesting than it might first appear: it’s challenging to differentiate between Tanacetum and Chrysanthemum visually; and many plants that we now classify in the Tanacetum genus were historically included in the Chrysanthemum genus (often as Chrysanthemum coccineum), with Tanacetum evolving as a more accurate and separate name through twentieth-century genetic research. This is similar to what I described for the plant well-known as Feverfew, whose names changed during the same timeframe (see Feverfew and Featherfew, or, Tanacetum parthenium (1 of 2)). Regardless of which of the 70 photos I ask PlantNet to help me name, I get similar results: Tanacetum coccineum is the most likely name; Chrysanthemum × morifolium is about half as likely; and Chrysanthemum indicum is the least likely, though not impossible, species name.

Given the ambiguity of plant identifications like this, I try to confirm their plausibility with additional research. Scientific name changes can make that as challenging as the initial identification; but I can often confirm it by searching other sources — like the Internet Archive’s Books to Borrow — to find out if the plant species has adapted to environmental conditions in the U.S. Southeast. While I won’t find something as precise as “this plant can thrive in Oakland Cemetery in Atlanta,” I can find out from books like Beautiful at All Seasons: Southern Gardening and Beyond by Elizabeth Lawrence or gardening books by Southern Living that the species has, indeed, adapted to southeastern conditions. And given that Oakland Cemetery (like many historical gardens and memorial spaces) often uses plants that aren’t regionally native and could even be considered exotic or come from other parts of the world, then the probability that Tanacetum coccineum is correct increases significantly.

With some confidence that we’ve got the plant name right, we turn to observing its visual characteristics to see what we can learn. When I come back from my photoshoots, I typically organize the photos by color similarity, in part because it helps me speed up my Lightroom workflow — since photos with similar colors and lighting conditions can often be edited with nearly identical adjustments — but also because it teaches me to observe the color variations that occur among flowers of the same species. If we take a broad view of my four-part series of photos, what emerges visually is a transition among three variations: plants with flowers that have a single dominant color; plants that produce flowers with blended colors among their petals; and plants that produce multiple flowers from a single stem that are each a different color. I had seen the first two color forms many times before, but this was the first year (I think) that I encountered the unique-looking variation producing two or three flowers of entirely separate colors.

Here I’ve assembled the whole series like a contact sheet; click for a larger version and you can see the transition I’m referring to. By the time we get to the end of the series, the plants that bloom in multiple distinct colors should be very apparent, and quite different from those — through about the middle of this series — that have either single-colored flowers or have petals with blends of yellow and pink or purple. This series also illustrates why Tanacetum coccineum sports the common name “Painted Daisy” — something that is more evident as we proceed through the middle and end of the series.

Researching either the garden or cultural history of the plants now classified separately from Chrysanthemum as Tanacetum can be fascinating. Even if you don’t get as botanically obsessed as I sometimes do, you’re likely well aware of the long association between chrysanthemums and Asian culture, with both Chinese and Japanese history having many embedded connections to chrysanthemums and closely related species. If we try to follow those traditions from ancient Asian culture to modern (and historical) gardens like those at Oakland, it can be helpful to work with a general framework for thinking that through, which could go something like this:

• There is a long, deep, and rich history of chrysanthemums in Chinese and Japanese culture. Tanacetum species plants, in that history, would have been known more for their medicinal uses than ornamental ones.
• There is a separate historical and botanical trajectory for Tanacetum that stems from its native regions (Iran, Turkey, parts of Russia, and the Caucasus region generally). This evolves into Tanacetum’s transition to European gardens in conjunction with plant exploration of that time, with Tanacetum coccineum making its way there in the early 1800s — where it was not initially distinguished from its visually similar chrysanthemum relatives.
• Since the nineteenth century, Europeans as well as Americans blended Chrysanthemum and Tanacetum plantings in their gardens and in memorial spaces like Oakland, where the historical differences between the two were less important than the plants’ botanical and visual characteristics — notably their ability to produce late fall/early winter color, withstand cold temperatures, and re-emerge perennially.
• We overlay this with the understanding that historical literature will often refer to what we now call Tanacetum as Chrysanthemum, or for a few decades, Pyrethrum, reflecting the plant’s three name changes over two centuries. The breeding work that produced the diverse color forms we see today began in the nineteenth century when the plant was still classified under those older names, with color diversity expanding continuously over much of the twentieth century.

With this framework in mind, we’ll explore more of the historical and botanical characteristics of Tanacetum coccineum and its linkages to chrysanthemums in the next three posts — or maybe we’ll just look at the photos!

Thanks for reading and taking a look!