A Garden of Marvels: Book Review

I always thought my garden held marvels, but until I read A Garden of Marvels: How We Discovered that Flowers Have Sex, Leaves Eat Air, and Other Secrets of Plants by Ruth Kassinger, I didn’t realize just how marvelous it was. And if you told me I was going to find a book on the history of plant physiology fascinating, I would have snorted. But there you have it: truth is stranger than fiction.

Kassinger is a gardener and writer after my own heart. She started writing this book after she killed a kumquat tree. (Her first book, Paradise Under Glass, also a good read, was about how she came to grow all sorts of unusual plants indoors.) She wanted to know why she killed it–where did she go wrong? Instead of googling the answer, she decided to learn more about the people who have made important discoveries about plants, and she tells their stories in a most entertaining way. Learning more about plants was never so easy, and I found myself amazed at all the things that have been discovered about plants since I took high school Biology–about four decades ago. (Really? Has it been that long?) As Kassinger puts it,

“A fern that vacuums arsenic out of contaminated soil, a biofuel grass that grows fifteen-feet tall, utterly black petunias, one-ton pumpkins, and photosynthesizing sea slugs are curiosities, but also instructive about how roots, stems, leaves, and flowers work.”

The chapter about black petunias was one of my favorites.

I did not know that the Petunia hybrida that makes up the bulk of petunias sold today is a cross between P. integrifolia and P. axillaris. I’ve grown P. integrifolia and I’ve grown an heirloom “climbing” petunia that I suspect shares the fragrance of P. axillaris. The explanation of why these two plants never cross in the wild was fascinating all by itself. As the woman responsible for breeding the Black Velvet petunia is explaining the plant’s genetics, I am amused to read that Kassinger is

…having a hard time concentrating. Actually, it is all I can do to resist stroking the petals, or, even more tempting, brushing my cheek against them. The amber flowers of one plant are exactly the color of toffee, and I stifle an impulse to nibble one.

Yeah, petunias can have that effect. Anyway, the archetypical plant discovery ensues. A weird, ugly, greeny-yellow-flowered petunia is acquired. It is crossed with lots of different breeding stock. Finally, out of a batch of two hundred seedlings, that one special plant emerges. As Ping, the breeder, relates

When we see it, Ping said, it is so surprising. It is black, black, black. Nobody can believe it.

I had heard of this petunia before, and had just assumed it was a very dark purple, as so many “black” flowers actually are. But, no:

Through genetic reassortment, this one individual expressed all the colors of the rainbow. With every visible wavelength absorbed, no light is reflected, and human eyes see no color at all.

(I have never seen this plant in person, but some photographs do make it look deep purple, not black.) Sadly, they could never get this special black-flowered petunia to breed true, so all Black Velvet petunias are grown from cuttings.

Each of the over two dozen chapters in the book is a mix of scientific discovery and human drama, and many of the stories eventually intertwine with each other, as one discovery builds on another. By the book’s end, Kassinger has bought another kumquat tree and shares how her care of this second tree has changed because of her newly acquired knowledge.

Tomorrow she will be writing here herself about growing kumquats. Her book also goes on sale tomorrow and I am very happy that my cold climate readers, at least, will have enough winter left to leisurely read it before the first snowdrops bloom. You will appreciate your spring garden that much more.

More on black petunias here

I received a pre-publication copy of A Garden of Marvels to review.