Originally a crop plant in Asia, Perilla frustescens var. japonica bears a resemblance to its close relatives, basil and coleus. Native to East Asia, it was brought to the U.S. by immigrants in the late 19th century. It may come as a surprise to some Western gardeners that perilla is a common culinary herb throughout Asia. In Japan, where it’s known as shiso, leaves, flowers and seeds are all used. The red form (akajiso) is used to dye pickled plum (umeboshi). Flowers (hojiso) are used for pickling and garnish.
Perilla’s distinctive flavor comes from perillaldehyde and other essential oils. The leaves are high in vitamins A and C, calcium, iron, potassium and riboflavin. They exhibit anti-inflammatory and anti-microbial properties. The oil derived from the seed is an source of omega-3 fatty acid and is available as a dietary supplement. The oil also has drying qualities similar to tung and linseed oils, and can be found as an ingredient in finishes.
Toxic to livestock, perilla is ordinarily avoided by cattle (which is one reason for its survival) but can be the cause of cattle poisoning when dried and combined with hay. The plant ketones cause pulmonary edema (fluid in the lungs) in many animals.
As a garden plant, perilla reminds me of those monster movies when, at the end of the film, the military troops move out of the city, sweaty and exhausted but relieved, having finally blown the beast to smithereens. The camera slowly pans to an abandoned warehouse, revealing the dimly-lit interior, and within a vast sea of oversize eggs, throbbing with sinister life.
Just like our fictional movie creature, perilla is extremely good at reproducing itself. Let it go to seed once and you’ve got a lifetime supply. Exhibiting the vigor that the mint family (Lamiaceae) is famous for, it can soon fill a space. In fact, it has naturalized in many locations from the Gulf of Mexico north to the Dakotas and New England. It does not yet appear on Connecticut’s invasive species list however.
Perilla is a plant that people love to hate. Grow one, let it go to seed, and you’ve got it forever. Some gardeners find perilla to be a nuisance because of this tendency to self seed so prolifically. Yet, in spite of its fecundity, it doesn’t usually overwhelm neighboring perennials and shrubs. It does a nice job of weaving through plantings unifying them with its deep purple color. The large, dark leaves are effective at shading out weeds. And, where it’s not wanted, it’s easy to pull.
For those who like to keep a tighter rein on their plants, a sterile cultivar , ‘Magilla Perilla’ is a tough annual common in the nursery trade. It has better endurance and sun-tolerance than coleus, which it closely resembles. It reaches about 3’ tall and wide by the time it’s killed by frost.