As long as we're on the subject of herbs and plant classification, there's something I'd like to share.
I hope you find it useful.
Herbs (short for herbaceous plants) are defined as "seed-producing, non-woody plants that die back to the ground annually".
The problem with that description is that it would include nearly every plant in existence except trees, shrubs, mosses, ferns, and funghi, while excluding obvious ones like rosemary, savory, bay, and sage, which develop woody tissues.
An even broader description, "a useful plant", could be applied to any of the 400,000+ species that make up the plant kingdom. All plants have purpose; some are just waiting to be discovered.
Culinarily, herbs are considered green leafy plants, whose leaves are used to add flavor, aroma, and color to food. Plants like lettuce, onions, broccoli, and tomatoes are all technically 'herbs', but we tend to categorize them as 'vegetables'. When cooks speak of herbs, we speak commonly of plants like parsley, dill, cilantro, etc.
When I began cooking with herbs eons ago, market selections were limited to fresh parsley, dill, basil, and mint. I quickly learned that the only way to gain access to a wider variety was to grow them myself. My first garden, in fact, was a culinary herb garden, where I strived to grow varieties that were esoteric at the time.
Herbs, I had been told, were the easiest plants to grow. I lost so many plants in those early attempts that I began to question my ability as a gardener.
But there were successes, and they led to an exciting period of discovery. Tasting things like lemon verbena, cinnamon basil, and anise hyssop for the first time opened up a new universe of flavor.
While I believed that the flavors and aromas found in herbs were varied and unique, I began to see similarities in their forms and in the way that the plants developed:
Thyme looked exactly like miniature oregano.
The leaves of green shiso and anise hyssop were nearly identical.
And the flowering heads of dill, parsley, cilantro, fennel, and chervil all resembled little umbrellas.
It was these observations (and many others) that led me to discover that most common culinary herbs belong to one of two families: Lamiaceae or Umbelliferae.
Undoubtably, my little discovery is common knowledge to anyone who really knows plants. But to me, it was an epiphany— a moment of clarity in which chaos became neatly organized.
As a gardener, it demystified the cultivation of herbs, allowing me to successfully grow individual species according to the traits of its family. Knowing that Lamiaceae likes heat and hates wet feet, I plant them in sunny locations where the soil is light and friable. And I know, too, that the tall flowers of Umbelliferae attract predatory insects like lady bugs and parasitic wasps, making them good companions to more vulnerable plants.
As a cook, the relationship between these seemingly disparate plants provided me with a deeper understanding of flavor. Questioning why lovage tasted like celery, parsley like carrots, and basil like mint, led me to investigate aroma compounds, and another universe opened up.
As a hunter and gatherer of information, I've amassed a good amount of knowledge about herbs and plants, most of which I've already forgotten. More and more, it seems that it's the connections that are forged through personal experiences and discoveries that are the truly indelible ones.
And just like herbs, they are all useful.