According to David Austin [David Austin's English Roses
, p. 17], Floribundas were the result of crossing Polyanthas with Hybrid Teas by P.T. Poulsen
. Poulsen was looking for roses that would thrive in the Scandinavian climate. Floribundas retain much of the hardiness, freedom and continuity of flower of the Polyanthas, but have much larger blooms.
[From The Quest for the Rose, p. 199:] 'Kirsten Poulsen' was originally classed as a Poulsen Rose, but later classified as one of the first Floribundas.
[From Gardening with Roses, by Judith McKeon, p. 32:] Floribunda roses are the result of crossbreeding between polyantha roses and hybrid teas. Compact bushy shrubs produce clusters of showy blooms, many of which resemble small, high-centered hybrid tea blooms, but they also come in a flat antique style and five-petaled or single-flower forms. An excellent landscape rose for borders, beds, and hedging, floribundas were introduced in the 1930s.
[From Roses, by Eleonore Cruse, p. 9:] larger flowers borne on shrubs of the same type as Polyanthas.
[From Gardening with Old Roses, Alan Sinclair writes on p. 58:] Floribunda roses are excellent for companion planting, and with their heritage of the Polyantha behind them, they are almost constantly in flower...
[From Roses For the Television Age, by E.A. Piester, p. 21:] 'Carillon' (1935) or 'World's Fair' (1938) may be credited with establishing the fashion for floribundas.
[From Roses of America, by Stephen Scanniello and Tania Bayard, p. 117:] Floribunda (cluster-flowered) roses are the result of crossing polyanthas and hybrid teas. Much of the original work on floribundas was done by Danish hybridizer D.T. Poulsen, who was attempting to raise roses that would flourish in the harsh winters and short growing seasons of Scandinavia. Poulsen introduced what is considered the first floribunda, 'Rodhatte', in 1912, and his sons Dines and Svend continued his work with this type of rose... At the beginning of the season, prune floribundas back by one-third to outward-facing buds. Clean out the centers, remove dead and cluttered canes, and shape the bushes to even heights in a bed.
[From Operation Roses, by Geoffrey G. Whitney, pp. 7-8:] For quantity of bloom and a blaze of color, throughout the season, they have no equals. Their hardiness and disease resistance is excellent and the color-range is wide and lovely!... most varieties lack fragrance...
[From Beautiful American Rose Gardens, by Mary Tonetti Dorra, p. 10:] Floribunda, for example, introduced as the "Hybrid Polyantha" in 1911 in Denamrk, grew taller and produced larger flowers and foliage than its parent.
[From Every Spray is a Lovely Bouquet, by Kitty Belendez, p. 13-14:] The single-petalled floribundas are usually the earliest to bloom in the spring, and they tend to recycle fairly quickly. For me, 'Playboy' is the first floribunda to bloom... The many-petalled floribundas take quite a bit longer to produce their sprays and will have their first bloom cycle even after most of the hybrid teas have finished their cycle... The biggest and best sprays are usually produced in the spring...
[From Value for Money, by Lt. Col. Ken Grapes, p. 114:] Of all the Floribunda roses perhaps the most famous is 'Iceberg' bred by Reimer Kordes and introduced in 1958.
[From A Year of Roses, by Stephen Scanniello, p. 41:] 'Smiles', a cluster flowered pink rose, was introduced as the first official floribunda in 1939.