Mary Helen Wingate Lloyd

Mary Helen Wingate Lloyd (1868–1934) was an American horticulturist who was a founding member of the American Iris Society and creator of a celebrated "iris bowl" garden.

Wingate was born in Brooklyn, New York (not yet a part of New York City) in 1868, one of four children of George Wood Wingate and Susan Prudence (Man) Wingate.

She married financier Horatio Gates Lloyd, Sr. (1867-1937), and redesigned the gardens on their estate, Allgates, in Haverford, Pennsylvania. The main house at Allgates was designed by Philadelphia architect Wilson Eyre, and the estate is now on the National Register of Historic Places. The centerpiece of Lloyd's landscaping was a bowl-shaped iris garden roughly 100 feet in diameter, consisting of four concentric terraces descending to a sunken grassy area with a tiled pool in the middle. By 1921, some 250 varieties of irises were planted in the bowl, with shorter irises towards the bottom. The bowl was divided into quadrants by stone staircases, and each quadrant was planted using a different color scheme, which Lloyd altered several times over the years. John Caspar Wister, the first president of the American Iris Society (AIS), held that it was "by far the finest" of the private iris gardens of the time.