In the article by The New Yorker, which was written after Untermyer’s death in March, 1940 by Geoffrey T. Hellman, the reader learns about another of Untermyer’s estates, Greystone, in New York.
It does mention that “during the last few years, Mr. Untermyer wintered in Palm Springs, where he died” (p. 58).
As mentioned previously, Untermyer was a lover of flowers. This article talks about his affection for floral, much from the author taking a tour of the estate in New York.
To read more about how The New Yorker talked about Untermyer, you can do so by viewing this PDF.