Today, there are lots of exciting new developments in the world of roses.
The popular hybrid tea rose appeared in 1867 with the introduction of ‘La France’. While these hybrids could withstand American winters better than their cousins, the China and tea roses, they were more susceptible to disease. With this vulnerability to fungal diseases, especially black spot, weekly or bi-weekly spraying of hybrid teas became necessary to protect them.
Since many municipalities and gardeners are now saying, “No” to spraying, it helps to explain why disease resistant Knock Out, introduced in 2000, has been such a resounding success. It has now outsold ‘Peace’, which had been the best selling rose of all time.
Today, gardeners have other options than just the Knock Out series. Leading the way in discovering which roses can stand up to the same rigors as Knock Out, Texas A&M has developed the Earth-Kind line of roses, which have outstanding disease resistance coupled with a high level of landscape performance.
Testing these roses is not a short-term proposition. It can take 10-20 years of testing to determine which cultivars match Earth-Kind standards. Traditionally, experts graded roses for their flower size, performance, and color. Evaluations for Earth-Kind are quite different: (1) attractiveness of form and flower, unaided by fertilization or excessive pruning, and (2) ability to withstand climatic conditions. All Earth-Kind roses grow on their own roots; grafting, fertilization, pesticides and fungicides are prohibited in these trials. The roses must also withstand drought conditions and receive little supplemental irrigation.
While these roses will survive without any care once they become established, for optimum growing you might want to occasionally feed them and water their roots on a regular basis during our long summers. Do not prune these roses as you would hybrid teas as many object to a severe pruning. As a general rule, never prune away more than one-quarter of the shrub.
Nineteen roses approved for the South now bear the Earth-Kind label: ‘Souvenir de St. Anne’s’, ‘Ducher’, ‘Mutabilis’, ‘Spice’, ‘Climbing Pinkie’, ‘Else Poulsen’, ‘New Dawn’, ‘Caldwell Pink’, ‘La Marne’, ‘Marie Daly’, ‘Perle d’Or’, ‘The Fairy’, ‘Belinda’s Dream’, Carefree Beauty™, Knock Out, ‘Sea Foam’, ‘Duchesse de Brabant’, ‘Georgetown Tea’, and ‘Mme. Antoine Mari’.
There are also many old roses that do not require fertilizing, watering and spraying, but cannot carry the Earth-Kind designation because they are not repeat bloomers.
Kit Flynn is a Durham Master Gardener and a member of the Advisory Committee of the Durham Garden Forum.