Roses in South Florida? Presented by: Doug Heighton St. Lucie County Master Gardener St. Lucie County Cooperative Extension 8400 Picos Road, Suite 101 Fort Pierce, Florida 34945 Tel: 772-462-1660 Website: http://stlucie.ifas.ufl.edu
History of a Florida Rose • Fortunianarootstock, (also known as Double Cherokee) is the rootstock of choice for a South Florida garden. • It was discovered in Ninghpo, China by Robert Fortune around 1848. • It offered a superior rootstock and hardiness, necessary for our nematode infested soils and our pests and diseases.
Mrs. B.F. Lampkin of Sarasota, Florida collaborated with Dr. Samuel McFadden, an ornamental horticulturist from the University of Florida. • Dr. McFadden’s tests discovered that Rosa fortuniana passed on great vigor to even weak varieties. • The rootstock was very heat tolerant, but sensitive to the cold. • It is more resistant to gall, stem die-back and root diseases.
It will live and produce longer than any other rootstock. • Some roses planted 40 years ago in Central Florida are now the size of trees! • Other rootstocks last approximately two years before they decline and die. • Fortuniana rootstock does well in all soils, except heavy clay. It will survive freezing temperatures if allowed to acclimate. • Rosarians all over the South are growing roses on Fortuniana rootstock.
Selecting Rose Cultivars • Old Roses, Old-fashioned Roses, Antique Roses • Existed before 1867 • Once blooming, an occasional repeat bloomer • More disease-resistant, less maintenance • Albas, Bourbons, Boursaults, Centifolias, Chinas, Damasks, Gallicas, Hybrid Perpetuals, Mosses, Noisettes, Portlands, and Tea roses. • Modern Roses: Hybrid Tea, Floribunda and Grandiflora Roses
Hybrid Tea • 1st hybrid tea, “La France” bred in 1867 • The most popular class of roses • Large flowers with a high-pointed bud • Repeat bloomers, blooming almost continually • One flower per stem on long sturdy stems – excellent for cutting • Large variety of colors • Upright shrubs
MISTER LINCOLN OLYMPIAD
Floribunda • Created around 1909 by crossing Polyanthus with Hybrid Teas. • Low growing bush with flowers produced in clusters • Usually more and smaller flowers on shorter stems • Well suited for landscape plants. They are often used for living hedges, borders, foundation covers, and to create mounds of color in the garden. • They tend to re-bloom faster than the average Hybrid Tea, are somewhat hardier, and put up with a lot of neglect. • They bloom throughout the season, with heavy sprays of richly colored blooms.
Grandiflora • The Grandiflora a cross of 'Charlotte Armstrong', a Hybrid Tea, and 'Floradora', a Floribunda. This rose is representative of the attempts at that time to produce a "different" rose (a mere 100 years after the first Hybrid Tea appeared) that would have the characteristic long stems, large beautiful blooms and pointed buds of the Hybrid Teas with the hardiness and flower clusters of the shrubbier Floribundas. • Grandifloras have a tendency to grow quite tall and produce full, large flowers. They come one to a stem as well as in clusters. The gangly growth habit is reminiscent of their Tea heritage. The individual florets are larger than the standard for Floribundas yet not usually as large as the huge blooms of the Hybrid Teas.
English Rose, David Austin Roses • Introduced in 1969 by David Austin of England. • An attempt to combine the best traits of Old Roses and Modern Roses – classic flower forms and fragrance of Old Roses on plants that repeat bloom like Modern Roses.
Miniatures • Diminutive forms of other roses • Originally derived from China roses • Grows from 6” to 18” in height • Quite hardy and can be grown in containers
Climber • This rose is hybridized to sprawl and must be trained to “climb” where you want them to. • Whatever pattern you create, be sure to tie down the tips encouraging blooms along the climbers arching canes.
Standard • Tree roses or standards are bushes that bloom atop a length of rosewood that has no growth along its sides. • They have two bud unions separated by a length of rosewood. • A hybrid is grafted to the top and rootstock to the base.
Where do we plant them? • Roses prefer full sun, a minimum of 6 hours • Morning sun is very helpful for it dries the leaves • Group roses together • Prepare a special well-drained area (raised beds) & add organics • Moderately acidic soil (pH 5.5 to 6.5)
What are these Amendments • Pre-planting soil amendments improve water holding capacity, the nutrient balance and change the soil reaction (pH) • Organics to use are: compost, leaf mold, peat, muck, sawdust, wood shavings and manures – use a 4” combined layer and mix thoroughly into a 12” depth of soil
Maintenance • Irrigate during dry or months of drought • 1 inch of water each week unless similar rainfall. • Water the day before spraying pesticide • Apply water the the soil surface not the plant surface
Use a complete fertilizer with a ratio of 3-1-2 • Fertilizer should be applied to plantings ~7 times per year (each time plants produce a flush of bloom) • Secondary plant foods can be supplied by organic or inorganic materials. • Use slow release • Check for deficiencies
Mulch with a 2-3” organic soil covering 2” away from the stem • Mulch reduces weeding and soil moisture loss and provides some nutrients to the plants • Use compost, wood chips, pine needles, sugarcane bagasse or other natural materials
Pruning • Remove suckers that develop from the rootstock below the graft by breaking them off, thereby removing all basal buds • Remove dead wood and canes showing stem disease symptoms when first noticed. Cut back to healthy wood and remove affected part from the garden • Major yearly pruning should be done in March and late August to avoid interrupting winter flowering • To avoid dieback and encourage rapid healing, pruning cuts should be made just above a dormant bud eye
Pests • Spider mites are tiny arachnids that feel like dust under the leaf. • They occur during hot, dry weather • They can be controlled by spraying soapy water every 7-10 days to knock down the webs • Spray undersides of leaves • May need to use a miticide SPIDER MITES
Aphids are tiny insects about 1/16 – 1/8 inch, green, red or black • They damage tender new growth • A hard spray of water or soap solution will remove aphid infestations. They reproduce every 7 days, treatments will need to be repeated • Ants have a mutual relationship with aphids APHIDS
Thrips are tiny insects that do cosmetic damage to roses by ruining the bloom • They may prevent a bloom from opening or cause discoloration of the flower • Thrips prefer light colored flowers • Control with systemic insecticide THRIPS
Sooty mold is a fungus that develops on the sweet honeydew excrement from sucking insects. • The insects that cause the secretion are located above the sooty mold • It is not harmful – but it is unsightly SOOTY MOLD
Blackspot is a fungus that causes black spots about 1/16 to 1/2 inch in diameter to form on the leaves • The infected leaves later turn yellow around the spots and eventually fall from the plant • Conditions promoting blackspot are wet leaves, splashing water and warm temperatures BLACKSPOT
Preventing Blackspot • Water soil not leaves • Remove all diseased leaves • Prune away crossing canes, open center of plant, allowing for air to circulate • Mulch well to minimize water splashing • A weak or stressed plant is more susceptible to disease • Alternate fungicides between systemic and contact or use a mixture of soap and oil
Powdery Mildew forms a white or grayish coating on the upper surface of young leaves and buds • Infected leaves crumple and become distorted • It thrives during high humidity but forms on dry leaves • Keep areas airy POWERY MILDEW
Anthracnose is a disease that is seen when cool, moist and humid conditions exist. • Anthracnose can be prevented by using a fungicide, but once the leaves are infected spraying won't do any good. Fungicides are effective in preventing disease infection but will not stop the disease once it has infected the leaves. ANTRACNOSE
Mosaic Virus causes interesting yellow patterns to form on some of the otherwise healthy leaves of the plant • Mosaic Virus can not be transmitted from one plant to another through pruning • It can be transmitted by grafting a healthy rose onto virused rootstock • Plants with a virus will live, but will not be as thrifty MOSAIC VIRUS
Key Points to Growing Roses • Location – minimum 6 hours of sun • Plant roses that have been grafted onto Rosa fortuniana rootstock • Select a rose variety based on care required • Weekly maintenance is necessary for disease and pest control • Proper pruning ensures the lasting beauty of your roses
Low Maintenance Evaluation • In 2008 a study was initiated by UF/IFAS to determine how 12 different roses would perform under identical low maintenance conditions in Fort Pierce, Plant City and Quincy. • After two years the Bermuda ‘Spice’ rose and Knockout ‘Radrazz’ rose performed best in Fort Pierce.
Bermuda ‘Spice’ Rose Knockout ‘Radrazz’ Rose See presentation material in American Society for Horticulture Science (ASHS) paper, 2010 http://ashs.confex.com/ashs/2010/webprogram/paper4162.html