Formal Gardens and a Bellflower Passion

bellflower (Campanula sp.)

bellflower (Campanula sp.)

Michael DeHart lives from the heart. He is a man generous with his time and with his knowledge. He is devoted to his work and says he will never give up his job.
DeHart is the horticulturist of the J. Paul Getty Museum.
After studying horticulture at Cal Poly San Luis Obispo, DeHart went to work for Disney World in Orlando, Fla. From there, he made his way back to California to assume his current position, where he and his crew are in charge of maintaining the formal peristyle garden at the Getty Museum in Malibu. He is also responsible for the remarkable herb and flower beds, located below and to the west of the peristyle, which the general public can miss.
“Every plant at this museum has two characteristics,” DeHart said. “First, it must be native to the lands that comprised the Roman Empire, and second, if indigenous to some conquered territory, it must ultimately have been cultivated by the Romans themselves. The Romans were famous for learning the uses of new plants from the peoples they conquered. They proceeded to take advantage of these discoveries culinarily and medicinally.”
Not only did the Romans seek to vanquish other people; they were determined to conquer nature as well. As a case in point, the Romans developed the highly formal garden, with its rows of geometrically perfect plants, shaped as boxes or globes, in symmetrical patterns. In the words of DeHart, “the Romans used symmetry as a way of showing off their control of the natural world.”
The Getty’s main peristyle, an open space surrounded by the evenly spaced pillars of a colonnade, contains a classic example of the formal Roman garden. The main lines consist of boxwood, which are punctuated on either side by bay laurel topiary trees and spheres of ivy. The Romans commonly created such large ivy globes, typically training them over huge rocks or boulders.
DeHart has had trouble with his boxwood, portions of which have died out and been replaced over the years. Amazingly, the peristyle garden is growing over concrete (the roof of the garage below), in only 18 inches of soil, which was imported when the garden was planted. Nematodes, which are microscopic parasitic worms, infest this soil and invade the roots of the boxwood. DeHart believes that the shallow soil and resulting root-bound condition of the boxwood has made the nematode problem more acute. DeHart soon will try to combat the nematodes with biological control techniques, including diatomaceous earth, beneficial nematodes that devour the pest nematodes and introduction of bacteria that infect and kill the nematodes.
DeHart has advice concerning the pruning of boxwood, whose leaves scorch when it is trimmed in hot weather. He does not prune in April or May, months that are famous in Los Angeles for their bristling heat, but waits for “June gloom” to set in, that period when a marine layer and overcast skies reliably linger overhead for several weeks. Following pruning in June, he doesn’t clip his boxwood again until temperatures cool and days are considerably shortened in late September.
While the formal peristyle garden at the Getty is unique in Southern California, plant lovers will linger at the adjacent vegetable and herb garden, which has many species that are seldom seen anywhere. “The Romans grew virtually every vegetable that we grow today,” DeHart said, “as well as some that we don’t.” Among these found at the Getty is the cardoon, a plant that closely resembles the artichoke, only its leaf stalks, not its flower buds, are cooked before being eaten.
Several types of thyme are highlighted, as well as two spellbinding, daintily mounding species of germander. Teucrium marum is a germander that, this time of year, is covered with pink flowers, while Teucrium subspinosum has a look as spiny as its name suggests. All of the beds are mulched with pumice, a pulverized volcanic rock that looks and feels like finely crushed brick.
The same mild Malibu climate that allows DeHart to grow a variety of plants that we Valley dwellers can only dream about is a restrictive environment when it comes to the cultivation of grapevines, beloved by the Romans. These plants require winter cold, which Malibu cannot provide, to produce a crop.
DeHart’s personal passion is for bellflowers, which belong to the genus Campanula. These plants produce captivating bell-shaped blooms, in a variety of sizes, that are violet, blue or white. He has collected a half-dozen different species at the Getty and is looking for more.
DeHart is showcasing Trifolium incarnatum or crimson clover, as a blood red, carefree ground cover. The Romans, who planted it in their wheat fields, believed that it had special mythological powers that made their wheat harvest more bountiful. They did not yet know that clover, like any other legume, simply adds nitrogen – the most important element in crop fertility – to the soil.
All the plants grown in these gardens are propagated by DeHart, whether from seeds or cuttings. Just beyond the gardens and museum, there is a propagation area, complete with a misting system for keeping cuttings hydrated and underground heating coils for stimulating root growth of young plants.
Now is the time to view the Getty Museum gardens in Malibu since, come July 6, this location will undergo renovation and be closed to the public until 2001. The Getty museum and its gardens, located just south of Topanga Canyon Boulevard on Pacific Coast Highway, are open to the public by appointment. For more information, call (310) 440-7300.

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