Botanist to Sonoma: Nature is ‘messy’

When is a weed not a weed? Just about always, thinks Peter Del Tredici.|

When is a weed not a weed? Just about always, believes Peter Del Tredici.

“I consider ‘weed’ to be a politically incorrect term,” he says. “There is no biological definition of the term weed. It’s really a value judgment.”

A research scientist from Harvard University’s Arnold Arboretum, Del Tredici has spent years exploring – and thinking about – the interaction between plants and people in the urban environment. It’s been said there are no weeds in nature, but in cities there are plants that may be unwanted but flourish nonetheless.

“Cities are built for people, first and foremost,” he has said. “We welcome nature, to the extent that it fits with a human agenda. We want nature to be a certain way – if it’s too weedy, or a problem, we don’t want that kind of nature.”

Del Tredici will be this year’s third and final guest in the Peter H. Raven Lecture series at Quarryhill Botanical Garden, on Saturday, Sept. 29. He follows snow leopard specialist Dr. Rodney Jackson and redwood ecologist Steve Sillett in this summer’s popular ?series, now in its third year.

Quarryhill President and Executive Director Bill McNamara calls Del Tredici “a highly respected scientist and author who offers a novel, some say ‘radically practical,’ approach to understanding the urbanization of plants.”

Del Tredici, 73, was originally from San Anselmo, but after getting his degree in zoology from UC Berkeley (and doing graduate work in Oregon) he went to Boston to build his career. Notably, his thesis topic was “The Evolution and Natural History of Ginkgo biloba L.,” a tree of special interest to friends of the Sonoma Plaza – the City of Sonoma considered removing a ginkgo last year due to the rank aroma of its seed droppings – and one he has continued to study throughout his life. (Why do ginkgos smell so strong? Ask Del Tredici, he knows the answer.)

The botanist was senior research scientist at the Arnold Arboretum for 35 years. His most recent book is “Wild Urban Plants of the Northeast: A Field Guide,” which describes the many species of urban plants that flourish without human support, making the case that they can be beneficial to the quality of urban life.

“Leaving nature alone works really well, but it’s messy – nature by itself is a messy thing. It doesn’t fit with our aesthetic goals particularly. So harmonizing all that with the human agenda is not an easy thing to do,” he cautions.

“Peter is a dynamic, thought-provoking speaker who will change the way you look at plants in our urban landscapes,” said McNamara.

Del Tredici’s lecture on “Urban Nature: Human Nature” will be Saturday, Sept. 29, from 5:30 to 6:30 pm, in the outdoor garden amphitheater at Quarryhill. Cost is $35 for members, $45 non-members. Refreshments will be available for purchase. Quarryhill is located on Highway 12 at 12841 Sonoma Highway. in Glen Ellen, and on the web at quarryhillbg.org.

Email christian.kallen@sonomanews.com.

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