We have fallen out of love with this word, perhaps because its synonym edible has supplanted it. You can find examples widely distributed in older literature, since it has been in English since the seventeenth century.
This is from the Milwaukee Advertiser of May 1838: “The common or garden asparagus, is one of the luscious esculent vegetables, with which tables can be furnished during the spring and early part of the summer.” We might well expect to find it in Mrs Beeton’s Book of Household Management of 1861. She does not disappoint us: “Among esculent vegetables, the Lettuce, Salsify, Scorzonera, Cardoon, and Artichoke belong to the family.” It’s also in the Journals of Lewis and Clark, in which Meriwether Lewis notes on 30 April 1806: “Many of those plants produce those esculent roots which form a principal part of the subsistence of the natives.”
You can also turn it into a noun for something edible. This is from a publication of 1921 by the English seedsmen Sutton and Sons: “Although the Cardoon is not widely cultivated in this country, it is found in some of our best gardens, and is undoubtedly a wholesome esculent from which a skilful cook will present an excellent dish”.