Albizia julibrissin silk tree

Silk trees in fragrant bloom echo the terracotta of the roof tiles, with lavender below, at Math Corner. Beyond the arches, coast live oaks line Lomita Mall, and George Segal’s “Gay Liberation” sculpture rises just above a boxwood hedge. Sairus Patel, 25 Jun 2017

Pink puffball flowers owe their color to tufts of stamens that fade to white at the base, the white itself yellowing with age and lending a salmon cast to the display. On each leaflet of the elegant, twice-divided leaves, the midvein is offset toward one side, almost at the margin, giving the leaflet the look of a tiny snap pea. Pods hang from the tree and can be quite ornamental; when dry, the seeds can be popped out easily and collected, germinating readily when soaked overnight. At night, the leaflets fold shut, likely as an adaptation to conserve moisture; on campus, this behavior can sometimes be seen in Acacia dealbata as well. Indeed, silk trees are closely related to acacias.

Landscape architect Thomas Church had about ten planted in the Math Corner courtyard in the Outer Quad around 1968; three remain, tall and limbed up. The dome-shaped crown lends itself particularly to campus settings viewed from above, where the flower color complements the terracotta of our tiled roofs. Replanting is warranted; the flowers of younger specimens are more readily appreciated.

One tree struggles in the western courtyard of Florence Moore Hall. Another stands where the Sonoma Terrace bike path enters Stanford Avenue. The faculty residential area has lost several, though some remain at 940 Cottrell Way and on the driveways of 818–820 Tolman Drive. A burgundy-leaved cultivar, ‘Summer Chocolate’, is at the Meyer–Buck Estate just west of the house.

The genus is named after a Florentine nobleman (his double z reduced to one in the process of Latinization) who in 1749 introduced it to cultivation in Tuscany from Constantinople; Borgo degli Albizi, a narrow and ironically treeless street, commemorates his family. Julibrissin is adapted from the Persian for silk flower.

Albizia julibrissin leaf. From Trees of Stanford and Environs, Ronald Bracewell