Learn it through the grapevine: Visiting botanist focuses on the flora of the Torah

If you’ve been putting horseradish in the maror section of your seder plate every Passover, it’s time to revisit that tradition. Horseradish is not a bitter herb and “is absolutely not maror,” insists ethnobotanist Jon Greenberg.

Save it for the gefilte fish or that thick slab of brisket on your plate.

Jon Greenberg of TorahFlora.org

Instead, think lettuce, arugula, chicory or even dandelion leaves, as maror is an herb that is mild when young and becomes increasingly bitter as it grows — mirroring the experience of oppression in Egypt.

But it’s not meant “to burn the roof of your mouth off,” says Greenberg, a New Jersey resident who teaches high school science at Abraham Joshua Heschel School in New York.

Greenberg, who runs the website TorahFlora.org, will be in the Bay Area over the next few days to lead two events focusing on botany and the Torah: a lecture and dinner at the Addison-Penzak JCC of Silicon Valley on Sunday, Dec. 22, and then a guided walk through the San Francisco Botanical Garden at Golden Gate Park on the morning of Wednesday, Dec. 25.

On the walk, he will point out plants cited in the Bible and the Talmud. Horseradish, he notes, was not one of them. But the garden includes amethyst sea holly (ergyngium), which qualifies as authentic maror, as well as the four species of the Sukkot ritual: etrog (citron), lulav (date palm), myrtle and willow.

At the JCC in Los Gatos, Greenberg will explore Torah through food and drink; topics include Noah’s wine vs. Pharaoh’s beer (both are on the dinner menu), edible lilies from Egyptian gods, Israeli gourmet products and the Jewish exile who taught Americans that tomatoes aren’t poisonous.

Now, back to horseradish. If it’s not maror — and was unknown in the Middle East — how did it get on the seder plate in the first place?

“It was a gradual process,” Greenberg says. “As Jews moved north and east in Europe, it became more and more difficult to get any kind of green vegetable in the spring.”

At first, the rabbis decreed that Jews could use horseradish leaves. Later, the root itself got the imprimatur, but in recent years, rabbis offer other choices. With two compartments for bitter herbs on the seder plate (maror and chazeret), lettuce can go in one slot, endive or arugula in another.

Jon Greenberg leads a biblical and talmudic botany tour. photo/courtesy jon greenberg

On his website, Greenberg, who holds a Ph.D. in agronomy from Cornell University, shares his thoughts on the relationship between Torah and plants. Ethnobotany, he writes, “is the study of how people use plants. Biblical ethnobotany is a way of using the tools of botany and ethnobotany to help us better understand the Torah.” That includes identifying biblical plants, understanding their symbolic and prophetic value, and studying their use in performing mitzvot.

For example, in a discourse on Psalm 28 — “May your children be like olive trees” — he points out that aged olive trees send up shoots surrounding its roots, and these shoots serve as windbreaks to protect the aging “parent.”

And then there’s the story of the mysterious “tree of the knowledge” in the Garden of Eden.

In the high school class he teaches on science and Torah, Greenberg looks at that story symbolically, using it as an opportunity to look at different ways of studying the relationship between humans to God and to nature. “Torah,” he says, “is not a book of history or natural history, but of metaphor.”

Citing midrash, he offers three possibilities for the notorious but unidentified tree in Eden: wheat, the etrog and the grapevine. Although wheat is not really a tree, he sees it as a symbol of human evolution from childhood to adulthood and from a state of hunting and gathering to an agricultural civilization.

The etrog, a fragrant, edible citrus, alludes to a time when all plants existed to serve humanity, he says.

The grapevine offers a more serious lesson: the need for self-discipline. Grapes have the potential to become wine, which can intoxicate. That may be a reason that observant Jews will look for a kosher seal not only on wine but on all grape products. However, no such prohibitions exist for beer and whiskey. That’s because for Jews in ancient times, “alcohol was wine.”

Greenberg, a frequent lecturer at synagogues, schools and botanical gardens, has also spent time in Israel, studying at a Modern Orthodox yeshiva. An observant Jew, he says much of his focus is on “using scientific information and historical information to help us in our Torah learning,” bridging the gulf between the scientific and religious mindsets regarding creation vs. evolution.

“I don’t see any conflict between the scientific account and the biblical account,” he says. “But they have different agendas.”


“Torah Flora: Biblical Botany and Beer,”
6-8 p.m. Sunday, Dec. 22 at JCC of Silicon Valley, 14855 Oka Road, Los Gatos. 21 and older only. Non-members $25, members $15. www.tinyurl.com/jcc-torah-flora or (408) 357-7411

“Biblical and Talmudic Botany Tour of S.F. Botanical Garden,” 10:30 a.m.-12 p.m. Wednesday, Dec. 25 at Golden Gate Park. Limited to 24 people. $10. Reservation required to jon@torahflora.org. www.torahflora.org