Toyon typically grows from 2–5 m and has a rounded to irregular top. Its leaves are evergreen, alternate, sharply toothed, have short petioles, and are 5–10 cm in length and 2–4 cm wide. In the early summer it produces small white flowers 6–10 mm diameter in dense terminal corymbs. Flowering peaks in June The five petals are rounded. The fruit is a small pome, 5–10 mm across, bright red and berry-like, produced in large quantities, maturing in the fall and persisting well into the winter.
Cultivation
Toyon can be grown in domestic gardens in well-drained soil, and is cultivated as an ornamental plant as far north as Southern England. It can survive temperatures as low as -12 °C. In winter, the bright red pomes are showy. Like many other genera in the Rosaceae tribe Maleae, toyon includes some cultivars that are susceptible to fireblight. It survives on little water, making it suitable for xeriscape gardening, and is less of a fire hazard than some chaparral plants. They are visited by butterflies, and have a mild, hawthorn-like scent. The fruit are consumed by birds, including mockingbirds, American robins, cedar waxwings and hermit thrushes. Mammals including coyotes and bears also eat and disperse the pomes.
Traditional use
The pomes provided food for local Native American tribes, such as the Chumash, Tongva, and Tataviam. The pomes also can be made into a jelly. Native Americans also made a tea from the leaves as a stomach remedy. Most were dried and stored, then later cooked into porridge or pancakes. Later settlers added sugar to make custard and wine. The Tongva ate the berries fresh, boiled and left them in an earthen oven for 2 to 3 days, roasted them, or made them into a cider. Pulveurized flowers were steeped into hot water to make tea which could be used to ease gynecological ailments. For stomach pains, bark and leaves are steeped in hot water to make tea. The same tea can serve as a seasonal tonic and ease other body pains. Also, applying mashed ashuwet to sores eases pain. Infected wounds are washed using an infusion of bark and leaves.
Toxicity
Toyon pomes are acidic and astringent, and contain a small amount of cyanogenic glycosides, which break down into hydrocyanic acid on digestion. This is removed by mild cooking. Most fruits from plants in the Rosaceae family, including apples, apricots, peaches, cherries, and plums, contain cyanide. Some pomes, though mealy, astringent and acid when raw, were eaten fresh, or mashed into water to make a beverage. A 2016 study found 5g of the dried berries to be safe. The study also found no cyanogenic compounds in the plant.
Legislation
In the 1920s, collecting toyon branches for Christmas became so popular in Los Angeles that the State of California passed a law forbidding collecting on public land or on any land not owned by the person picking any plant without the landowner's written permission. Toyon was adopted as the official native plant of the city of Los Angeles by the LA City Council on April 17, 2012.
Taxonomy
The genera Photinia, Aronia, Pourthiaea, and Stranvaesia have historically been variously combined by different taxonomists. The genus Heteromeles as originally published by Max Joseph Roemer was monospecific, including Photinia arbutifolia Lindl., as H. arbutifolia M. Roem, but the name was illegitimate because it included the type of the genus Photinia. This has since been corrected by conservation, and the name is therefore often written as Heteromeles M. Roem. nom. cons..
Phytochemistry
The plant has been used as a treatment for Alzheimer's by indigenous people of California and recent research has found a number of active compounds that are potentially beneficial to Alzheimer's treatment. These include icaricide compounds, which protect the blood-brain barrier and prevent infiltration of inflammatory cells into the brain.