Ambrose Christian Congreve (14 April 1907–28 May 2011) was an Irish industrialist, best known for his world-famous garden at Mount Congreve. He won 13 Gold Medal awards at the Chelsea Garden Show in London for this garden.
He was the son of Major John Congreve and Lady Helena Blanche Irene Ponsonby, the daughter of the Eighth Earl of Bessborough. As a businessman he ran Humphreys & Glasgow, the gasworks manufacturers and petrochemical engineers, from 1939, when he took over from Dr Arthur Glasgow, his father-in-law and a co-founder of the firm. He remained there until 1983, when the company was sold to an American concern. However, his abiding passion was gardening, especially at Mount Congreve, near Kilmeaden, County Waterford.
The Mount Congreve estate lies just outside the village of Kilmeadan. It is famous the world over for its rare species of plants and also its plant nurseries. It consists of around seventy acres of intensively planted woodland garden and a four-acre walled garden. In addition there are an 18th-century house (the ancestral home of Ambrose Congreve), ranges of glasshouses, more than 16 miles of paths and a wholesale nursery. After Congreve's death, aged 104 years, the Mount Congreve estate was left to the Irish State.