Henrietta Knight, Baroness Luxborough (née St John; 15 July 1699 — 26 March 1756),[1] was an English poet and letter writer, now mainly remembered as a gardener.

Horace Walpole's correspondence suggests she was caught by her husband in flagrante delicto with her doctor, whilst other sources add a further lover in the form of a young cleric named John Dalton (1709–1763).

[4] Dalton had been employed as tutor to the children of Henrietta's close friend Frances Thynne (1699–1754), known until 1748 as Lady Hertford, wife of Algernon Seymour, 7th Duke of Somerset.

Henrietta Knight went to live on her husband's estate at Barrells Hall, which she had laid out in the emerging style of English landscape gardening.

[5] Dying towards the end of March 1756, Henrietta Knight was buried in the church of Wootton Wawen; her remains were later removed to a mausoleum near Barrells Halls.

The poems deal with the weather or nature, and in particular, the sprit of English landscape gardening is expressed in: Written at a Ferme Ornee near Birmingham; August 7th, 1749.

Other correspondence appeared in Thomas Hull's Select Letters between the late Duchess of Somerset, Lady Luxborough … and others, London, 1778, 2 vols.

[3] By Lord Luxborough, she had a son, Henry, who married, 21 June 1750, a daughter of Thomas Heath of Stanstead, Essex, and died without issue in the lifetime of his father.