Fraxinus americana
white ash

Oleaceae (olive family)
Eastern United States
Autumn Purple ash
Autumn Purple ash (Fraxinus americana ‘Autumn Purple’), our reliably earliest fall color, in the sunken garden behind Thornton Center. Chor Seng Tan, 19 Oct 2017

Pinnate leaves about 10 inches long with five leaflets, smooth green on top and pale and possibly furry underneath. The fruit is a hanging winged seed 1 or 2 inches long. There is a large one west of Encina Commons off Galvez Mall (planted in the 1890s), one at the south end of Lasuen Street on the side toward the Oval, and others in the vicinity.

Autumn Purple ash

Fraxinus americana ‘Autumn Purple’ on California Ave, Palo Alto. Sairus Patel, 18 Oct 2017

F. americana ‘Autumn Purple’ is a male selection that has started to be used in Palo Alto since the early 2000s. More golden with gentle, peachy orange-rose sections – with some russet highlights here and there – than purple, it is our earliest fall color, lighting up in October and going mostly bare by Halloween.

An impressive planting on campus is in the sunken garden at the old Terman Center location, behind Thornton Center. A couple of dozen flank the pathway down to the fountains from Thornton. For some reason, the grouping on the right (as you descend the stairs) are twice the height and trunk width than the grouping on the left. Surely they get the same surrounding lawn irrigation; perhaps the batches of soils used on each side differ enough. Note the distinct graft line at the base.

In Stanford Research Park nearby, a sidewalk allee of Autumn Purple ash fronts a row of coast redwoods (Sequoia sempervirens) on California Ave, at 2475 Hanover St. They were planted in 2004. The ample irrigation and nearby lawn didn’t seem to have resulted in particularly fast growth, but they have been picking up about twelve years later. The allee flanks a sidewalk built over Engineered Soil Mix, part of Palo Alto’s “structural soil” program. Observe the trees’ thick, snake-like surface roots; perhaps root-bound nursery stock explains their slower-than-expected initial growth. The delightfully perky winter profile of the canopy is almost a cartoon of a symmetrical, neatly branching tree, at least at this stage of their life.

Name derivation: Fraxinus – classical Latin name for ash; americana – American.

About this Entry: The first paragraph of this entry is from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. The section on Autumn Purple was added Oct 2017 by Sairus Patel.