Just as it’s getting cold and nasty out, I see the third movement in the street-tree symphony is well underway: Chinese pistache trees are resounding with color. After the young tupelos’ blast and the short, single-note fanfare of ginkgoes, their fiery crescendo will give way to the sustained theme of sweetgum for the rest of the winter; hopefully before I run this metaphor completely into the ground.
The Chinese pistache, Pistachia chinensis (big surprise), was introduced to the West by the legendary British plant hunter Ernest H. “Chinese” Wilson. It would be a stretch to say he discovered it, since the Chinese were well aware of its existence and virtues. In his memoir A Naturalist in Western China, which we happen to have in the house because Joe is a sucker for books whose titles start with A (or The) Naturalist in …, Wilson writes that his Szechwanese hosts called it huang-lien shu, cooked and ate its young shoots, and used its logs, especially those with a natural fork, as the rudderposts of boats.
Aside from its sheer gorgeousness, it’s valued in California as rootstock onto which the commercial pistachio, P. vera, is grafted.
Wilson, a native of Chipping Campden, went to China in 1899 in the service of Veitch and Sons Nurseries. The elder Veitch had warned him: “My boy, stick to one thing you are after and do not spend time and money wandering about. Probably almost every individual plant in China has now been introduced into Europe.”
Dead wrong. Wilson returned to England with 35 Wardian cases’ worth of plant material, including many species new to “Western” science. Among the 1,500 Chinese plants he brought into the horticultural trade are royal lily, paperbark maple and kiwifruit. Later forays for Boston’s Arnold Arboretum took him to India, Australia, New Zealand, the American tropics and East Africa. After all that, Wilson died young, in a motor vehicle accident near Worcester, Massachusetts.
Lately, Chinese scientists have called Chinese pistache “a superior species for biomass energy with high oil content in seeds.” This might be homie boosterism; I don’t know. The seeds are really small; there are lots of them but only on female trees and usually in significant quantities only after the trees are 15 to 20 years old. They’re in the berries that turn blue when ripe—look for them now, because they contrast with the remaining foliage—and birds eat them.
Beware of picking them, however. They have the same potential for skin irritation as the rest of the Anacardiaceae family. Relatives include P. terebinthus (formerly a source of turpentine), and P. lentiscus and P. cabulica, both sources of mastic, an edible resin used as chewing gum (which one masticates, see) and a flavoring agent.
Chinese pistache is considered invasive in Texas, probably because of those bird-dispersed seeds. The California Invasive Plants Council started looking hard at the species in 2006 but, as far as I know, hasn’t listed it yet, though it’s “established” in Butte, El Dorado, Sacramento, Yolo, Riverside, San Bernardino and San Diego counties. Oddly enough, it’s not considered invasive in Florida.