The 2010 ASHS Annual Conference

The original rose cultivars planted at Mississippi State University Veterans Memorial Rose Garden were evaluated during the period of 2007 – 2009. Thirty one cultivars belonging to the horticultural classes Floribunda (F), Grandiflora (Gr), Hybrid Tea (HT), or Shrub (S) roses were grown in raised brick beds since April 2006. Cultivars are grown on own root, or grafted on R. x fortuniana or ‘Dr. Huey’ rootstocks. Cultivars on R. x fortuniana rootstock are favored by exhibition rose enthusiasts in lower southeastern US for vigor and performance. ‘Dr. Huey’ rootstock is a common understock for roses, particularly in hot climates. All roses at the rose garden are maintained under a systematic spray program and are regularly deadheaded, as they are publicly displayed. Data on plant height, plant width, number of canes per plant, and ratings for black spot, incorporating both defoliation and infection, were collected at end of growing seasons in 2007, 2008, and 2009. The Horsfall-Barratt rating scale was used to generate scores for black spot (Horsfall and Barratt, 1945). In 2008 and 2009, end of season visual plant performance was assessed by rating flower quantity and quality, foliage quantity and quality, and plant habit and vigor on a scale of 1 to 10. After 3 years sufficient growth patterns were established to definitely separate the cultivars into large, medium and small growing roses. Most of the large roses were hybrid teas on R. x fortuniana rootstock. Medium sized roses were hybrid teas and a grandiflora grafted on either rootstock and small sized roses were either hybrid teas on ‘Dr. Huey’ rootstock, floribundas or a groundcover shrub rose. Growth data describes individual cultivars well. Tall and wide roses with few canes indicate an open architectural structure.  Roses with many canes are bushy in presentation.  Quality ratings help describe the overall health of the rose in terms of both blackspot incidence and strength of the rose at the end of the growing season.  This has implications for the health of a rose going into winter conditions. Information is presented in a format that is useful for growers and homeowners to make informed choices that suit their conditions.