Ailanthus must have been widely planted by New York City in the 19th century. The great American author Henry James mentions Ailanthus in his description of Washington Square in the book of the same name (1880), excerpted by PBS.
The ideal of quiet and of genteel retirement, in 1835, was found in Washington Square, where the doctor [sic] built himself a handsome, modern, wide-fronted house, with a big balcony before the drawing-room windows, and a flight of white marble steps ascending to a portal which was also faced with white marble. This structure, and many of its neighbours, which it exactly resembled, were supposed, forty years ago, to embody the last results of architectural science, and they remain to this day very solid and honourable dwellings. In front of them was the square, containing a considerable quantity of inexpensive vegetation, enclosed by a wooden paling, which increased its rural and accessible appearance; and round the corner was the more august precinct of the Fifth Avenue, taking its origin at this point with a spacious and confident air which already marked it for high destinies. I know not whether it is owing to the tenderness of early associations, but this portion of New York appears to many persons the most delectable. It has a kind of established repose which is not of frequent occurrence in other quarters of the long, shrill city; it has a riper, richer, more honourable look than any of the upper ramifications of the great longitudinal thoroughfare–the look of having had something of a social history. It was here, as you might have been informed on good authority, that you had come into a world which appeared to offer a variety of sources of interest; it was here that your grandmother lived, in venerable solitude, and dispensed a hospitality which commended itself alike to the infant imagination and the infant palate; it was here that you took your first walks abroad, following the nursery-maid with unequal step, and sniffing up the strange odour of the ailanthus-trees which at that time formed the principal umbrage of the square, and diffused an aroma that you were not yet critical enough to dislike as it deserved; it was here, finally, that your first school, kept by a broad-bosomed, broad-based old lady with a ferule, who was always having tea in a blue cup, with a saucer that didn’t match, enlarged the circle both of your observations and your sensations. It was here, at any rate, that my heroine spent many years of her life; which is my excuse for this topographical parenthesis.
According to James, Washington Square was the “ideal…of genteel retirement”, full of “inexpensive vegetation”, “rural and accessible” in appearance, having a “riper, richer, more honourable look” than more tony parts of town. The Square was mostly planted up with Ailanthus:
it was here that you took your first walks abroad, following the nursery-maid with unequal step, and sniffing up the strange odour of the ailanthus-trees which at that time formed the principal umbrage of the square, and diffused an aroma that you were not yet critical enough to dislike as it deserved
I had to look up umbrage. I knew it meant offense, but that didn’t seem to make sense. The principal meaning is shade! Offensive shade – I don’t know if James intended to give that connotation, but I think it fits rather well.
Many thanks to Christine for the link.