[2] In 1921, Alfred Burgess imported some hybrid cultivars of tall bearded iris, and two years later Jean was given responsibility for their propagation and sale.
Her first success was the Destiny hybrid, which Geoffrey Pilkington, the secretary of the Iris Society, promoted for release on the British market.
Jean started working on a new challenge: to widen the colour range of tall bearded irises known as amoenas—that is, those with white standards and violet, violet-blue, or purple falls.
[1] In 1949, Stevens introduced Pinnacle, a very fine white and yellow amoena that gained international recognition and became one of the world's most popular iris cultivars.
[1] Jean went on to create amoenas in a range of other colours, including deeper yellow, pale blue, plum, and pink shades.
[2] In 1967, her amoena 'Sunset Snows' with its cocoa-tinged pink falls took third place at an international iris competition in Florence and won cups for the best early variety and for the most original colour, marking the first time a prize in the competition had gone to the southern hemisphere and the first time that a single cultivar had collected three different prizes.
Administrative difficulties led to her recommending a separation of the two bodies, and one result of the split was that she cofounded the New Zealand Iris Society with C. A. Teschner and D'Arcy Blackburn in 1949.
[1][2] Jean and Wallace Stevens also led the way in developing native Australasian and South African flora for cut-flower production, especially proteas and Leucadendron.
[2] In the early 1960s, the Stevenses faced losing part of their land to a proposed primary school, but their appeal was supported by New Zealand and British horticultural authorities and was upheld.