Maple married Emily Harriet Merryweather, and the couple had one surviving daughter, Grace Emily (1876–1950). She was married twice and had four children, each by a different father. In 1896, Grace married Baron Hermann von Eckardstein, who was First Secretary of the
German Embassy in 1898 and later Ambassador to the Court of St James. They had one child together, Kathleen "Kit" (b. 1899). In 1906, Grace had a child, Reginald Benwell, by another man, Dr. C. J. Williams; this child was adopted out secretly because Grace was still married to von Eckardstein. The date of their divorce is unknown. On 16 August 1910, in
Metheringham parish church, Lincolnshire, Grace, still known as "Baroness von Eckardstein", married
William Ernest George Archibald Weigall, an MP and later governor of South Australia and a
baronet. Six months into the marriage, Grace gave birth to her third child, Heather Campbell (b. March 1911). She was adopted out secretly because her father was Elidor Campbell, son of the 3rd
Earl Cawdor, a fact Heather did not discover until very late in her own life. Heather married New Zealand artist
Arthur Gordon Tovey and later published a memoir about trying to discover her parentage,
Searching for Grace (2010). In 1914, Grace bore her husband a daughter, Priscilla Crystal Frances Blundell Weigall. The Weigalls lived in a country house called Petwood at
Woodhall Spa, Lincolnshire. Petwood is so called because Lady Weigall had it constructed of her favourite wood, her "pet wood". Lady Weigall turned her former home into a hotel in 1933 when the Weigalls moved to Ascot. Petwood was requisitioned by the RAF during World War II. Towards the end of the war it was used as the Officers' Mess for the famous
Dambusters 617 Squadron, which was then based at nearby
RAF Woodhall Spa. Inside the hotel, the Squadron bar is dedicated to the brave men of 617 Squadron and has memorabilia from that period.
Other descendants Grace's granddaughter, Priscilla Weigall, was first wife (1935–1943) of
the 6th Earl Howe (1908–1984) by whom she had two daughters. One of Sir John's great-great-grandsons is actor
Jake Weber. ==Arms==