SPECIAL TOPICS: ROSES

The rose continues to be one of the world's most popular flowers. For centuries, roses have been cultivated for garden landscaping and as plants supplying cut flowers for the home. Improved cultivars available today have increased this long-standing appreciation of roses as flowering shrubs.

In Florida's year-round gardening climate, the rose is an evergreen shrub that will continue to increase its flower production for at least five years. Roses grow and bloom all year in southern and central Florida. A rose bush can supply more blooms suitable for cutting than any other flowering shrub. Each year plants produce from five to seven cycles or "flushes" of bloom--of one to two week's duration--and a few flowers between cycles.

In Florida roses are high-maintenance plants. Plentiful supplies of high quality roses can be obtained only when the plants are cared for properly and allowed to reach mature size. Plants require grooming over a long blooming period and they require weekly applications of fungicide to control the leaf disease blackspot. But, for those who like to spend time in the garden each week, growing roses can be a rewarding hobby.

Leaves manufacture food for growth. Preventing early loss of foliage means controlling mites and the fungus that causes blackspot. Producing high-quality flowers means using seasonal control practices for thrips and for the fungus that causes powdery mildew.
While most features of Florida rose culture are the same as in other regions, there are some differences. Plants grow larger here and should be given more space than those in colder climates. Winter protection practices such as deep planting or covering the tops are not necessary, but it is necessary to anchor taller varieties to reduce wind injury. Here, as elsewhere, success depends upon the selection of varieties and rootstock suited to local conditions. Everblooming varieties grafted on Rosa fortuniana rootstock are recommended, but ever-blooming varieties with other kinds of root systems can be grown successfully.

For more information go to: http://edis.ifas.ufl.edu/MG036
Rose Culture. S.E. McFadden and R.J. Black. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: January 1979. Reviewed and revised: 1985, 1990, 1991, June 2004.

PURCHASING ROSES

Before buying a rose, it's important to consider its root system. Florida cooperative experiment stations tests have determined that roses grafted on Rosa fortuniana rootstock grow larger and more vigorously, produce more flowers and live several years longer than plants grown on any other rootstock.

Grafted plants are composed of two different roses; one forms the root system (rootstock) and the other the top (scion). Most rose plants sold have been grafted on one of three different rootstocks.

Of the three standard rootstocks, Fortuniana (Rosa fortuniana), Double White Cherokee or Evergreen Cherokee gives the best results. Dr. Huey (Shafter) is second best. Multiflora (Rosa multiflora) is the least satisfactory.

Plants referred to as "tree roses" are grafted on 1 to 3’ stem lengths of the rootstock variety rather than on the 6” lengths used to produce bush-form plants. Plants on their own are on the market and are satisfactory for the older shrub varieties. Dwarf cvs are frequently sold on their own root, but perform better when grafted.

Field-grown plants, one to two years old, are available from out-of-state sources between October and March. Nurseries transplant dormant plants into containers, maintain them for about three months, then market them in bloom. Much of the risk involved in early handling of dormant field-grown plants is absorbed by these nurseries. Rose plants marketed from one source are not all equally well formed.

Grading serves to distinguish the better plants from poorly developed ones. The superior-grade plants give better results than inferior grades. Dormant rose plants are graded Florida Fancy, Florida Number 1 and Florida Number 2, based on size and number of canes.

Container-grown roses should be grown in the container in which they are marketed for a minimum of one month of the active growing season and for a maximum of two growing seasons. They should be sold by rose grade as specified above and the containers should be at least three gallons in capacity.

For more information go to: http://edis.ifas.ufl.edu/MG036
Rose Culture. S.E. McFadden and R.J. Black. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: January 1979. Reviewed and revised: 1985, 1990, 1991, June 2004.

ROSE GROOMING

Grooming is a regular feature of rose culture. It consists of selectively trimming at regular intervals to keep plants healthy, attractive and productive. Removing faded flowers after each flush of bloom improves plant appearance and prevents fruit development. This conserves food and encourages new growth.

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 Remove the lateral flower buds as they form, allowing one bud to mature on each stem.
• Pinch out all flower buds as they form until 28 to 34 days before flowering is desired.
• Flower buds should be removed for the first two months after planting to encourage growth and to help to establish a new plant.
• The first flowers should be cut with short stems to leave as much foliage as possible on the plant.
• Plants should be well established before flowers are cut with longer stems, and then only cut the length of stem needed.
• Remove suckers (leafy shoots) that develop from the rootstock below the graft union by breaking them off rather than by cutting in order to remove all basal buds, recognized by their location and their different leaf appearance.
• Remove dead wood and canes showing stem disease symptoms as soon as you notice them. Cut affected part back to healthy wood. Remove affected part from the garden area.
• Prune twice each year to keep plants to a manageable size during March and late August to avoid interrupting winter flowering.
• To avoid die-back and encourage rapid healing, pruning cuts should be made just above a dormant bud (eye). When entire branch is removed, make smooth cut at point of juncture.

When cutting flowers, consider the arrangement in which they are to be used. Larger, more open flowers to be used low in the container need less stem length than tighter buds, used for height.

Cut buds after the green sepals fold back toward the stem and the outside petals loosen and start to unfurl. Blooms cut in tighter bud will fail to open. Use a sharp knife or pruning shears for cutting flowers and make a clean cut just above a well-developed, five-leaflet leaf. Die-back may result from leaving a ragged cut or a long stub above the dormant bud.

Re-cut rose stems under running water to encourage longer lasting blooms. Flower preservatives are also very effective for roses. Do not store roses in the refrigerator with produce.

Black Spot of roses is the principal disease problem with roses in our area. Weekly spraying will be required in the rainy season, especially on the fancier hybrid roses. Old favorites like Queen Elizabeth require less spraying. Aphids and Thrips are the most common insect issues. Regular preventative spraying with a systemic insecticide is recommended to stay ahead of insect peasts.

A schedule of rose maintenance includes: spraying each week, grooming and fertilizing after each flush of bloom, pruning and mulching during each winter season. Balanced fertilization, especially with micro-nutrients and a lot of light are essential to producing healthy prolific roses.

 
For more information go to: http://edis.ifas.ufl.edu/MG036
This Information sheet contains information taken from Rose Culture. S.E. McFadden and R.J. Black. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: January 1979. Reviewed and revised: 1985, 1990, 1991, June 2004.