The Padua Botanical Garden, recast on the Arbor Terrace at Dumbarton Oaks. (Luis Marmol/Dumbarton Oaks)

At first blush, the dozens of clay pots on the Arbor Terrace at Dumbarton Oaks seem like the treasures of a plant nerd just back from a shopping spree. In one grouping alone, you find an array of thyme, oregano, lavender, scented geranium, sage, sweet woodruff and mint.

Step back, and you see a method to this madness: The pots are arranged in a decorative circle, and for all their variety, they share one trait. They are all herbs. Culinary herbs, household herbs, healing herbs. Actually, they share something else: They were also recorded in the Padua Botanical Garden in northeastern Italy. The garden was first planted in 1545 and is the oldest surviving example of a university teaching garden. Here, medical students learned to identify plants and their pharmaceutical qualities. In an age when we have come to think of plants as mostly decorative or edible, such “physic” gardens are a reminder of a time when we needed herbs and knowledge of them to survive.

The gardeners at Dumbarton Oaks — the Georgetown estate and Harvard research institution — re-created the Padua garden to mark a gathering of scholars in May to explore the historic link between landscape and academia. That gathering is past, but the display on the Arbor Terrace, which includes an accompanying outside exhibit, will remain until midsummer.

Dumbarton Oaks is well positioned to know what was grown in a 16th-century Italian botanic garden; its world-renowned collection of rare garden books is broad and deep. Librarian Linda Lott pointed gardener Luis Marmol to a 1713 tome titled “Catalogus Plantarum,” a record of the Padua plantings.

Some of the book’s illustrations are reproduced in the exhibition under the terrace’s big-boned wisteria arbor. The images are flat and distorted, but the plants are recognizable. They include a rose, a currant, a plantain, an arum, an aloe and, yes, marijuana. (The gardeners have forgone the living version in the display.)

The copper beech in the Bishop’s Garden at Washington National Cathedral. (Adrian Higgins/The Washington Post)

The link forged by the book between the Padua garden and Dumbarton Oaks would be cool enough, but the threads are even more intertwined and interesting.

Around the turn of the last century, the novelist Edith Wharton returned from her grand tour to write a book describing Italy’s great villas and their gardens by region. She briefly described Padua’s Orto Botanico, along with a drawing she made from memory. Wharton recounted a perimeter wall that formed a large circle, broken by four gates and their paths. The beautiful old brick wall, she wrote, was topped with a marble balustrade “adorned alternately with busts and statues.”

The beds within were arranged by plant type and use, and subdivided by iron railings and stone edgings. All these barriers had more than an ornamental function: They were there to help prevent visitors from stealing plants.

The garden persists and appears little changed from Wharton’s time, or even the 16th-century version.

Wharton’s niece, Beatrix Jones Farrand, was not only a top landscape designer but also the principal architect of the gardens at Dumbarton Oaks. Although her aunt’s account of the Padua garden was brief, it stuck in her mind, and Farrand set about creating a version of it at Yale — two of the four quadrants were incorporated into a botanic garden developed in the 1920s. She was working on Dumbarton Oaks at the same time, for the pre-Harvard owners, the Blisses. Marmol wonders whether some of the design details were subtly incorporated into the Arbor Terrace.

A few of the rectangular pavers were removed for the garden’s central feature — a stylish modernist fountain — but to remove more to allow planting directly in the ground would not have achieved the circular look of the Padua garden, said Gail Griffin, director of gardens and grounds. Hence the dominance of pots. This is a boon to visitors looking for ideas, because you could create your own modest version of Orto Botanico on a patio or balcony without the need for plant beds.

At the very least, the Padua display offers an excuse to visit Dumbarton Oaks now that the warmth has arrived, finally, and coaxed the rose garden above the Arbor Terrace into its annual ball.

Before our record-breaking cold, damp May fades into memory, you might also want to savor the silver lining of that cloud. For purple-leafed shrubs and trees, temperatures that ran about 15 degrees cooler than last year preserved the intensity of pigments that color the leaves. Run out and drool over the cotinus or smoketree (Royal Purple is the standard purple version); upright and weeping Japanese maples, the Forest Pansy redbud; the purple-leaf plums; and, if you have one, the redleaf Chinese loropetalum.

The king of the purple plants is the copper beech, which can reach 80 feet tall and 60 feet across. In the Mid-Atlantic, the heat and warm nights of summer take a lot of the drama out of it, but in its first month after leafing out, the copper beech is the black hole of the garden, grabbing all the light in its orbit and bending your gaze toward it. This season has been quite spectacular.

At Dumbarton Oaks, there used to be an old specimen near the Lover’s Lane Pool, but it got old and died a few years ago. Its replacement, now in place for a few seasons, has a four-inch caliper trunk and is beginning to have some presence.

I noticed a stunning mature specimen on the south side of the Bishop’s Garden, below the Washington National Cathedral. Two benches beneath it invite you to shelter in its canopy. It would also be a great place to escape the drizzle of May or the bright heat of June. You don’t need an Italian villa to feel like a prince. You just need a place at the beech.

adrian.higgins@washpost.com

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