SUBROSA
Number 45   November - December 2005
                 

LOW MAINTENANCE ROSES FOR PUBLIC GARDENS

By Steve Huddleston, Fort Worth Botanic Garden, and Gaye Hammond, Houston Rose Society

No public garden would be complete without a spectacular display of roses. Not only does the ?Queen of Flowers? embellish our public gardens, she also provides stunning floral backdrops for the marketing pieces we rely on to attract visitors to these public venues. Simply stated, visitors expect to see roses when they come to a botanical and/or public garden.

Unfortunately, the rose?s reputation for being a temperamental, hard-to-grow, chemically-dependant plant is legendary. This means horticulturists must implement regular spray programs for fungal/pest problems and add copious amounts of fertilizers to rose gardens in order to achieve and sustain high bloom production. While the home gardener may be able to spray and fertilize a manageable number of rose bushes on a regular basis and achieve satisfactory results, maintenance in public gardens is more problematic. In public gardens horticulturists must also contend with (1) limitations on personnel resources and volunteer availability, (2) financial and budgetary constraints, and (3) meeting the high expectations of garden visitors by keeping their gardens in year-round, picture-perfect condition. These issues are easily overcome with the inclusion of EarthKind? roses in public gardens.

Roses which have received the coveted "EarthKind?" designation have been subjected to rigorous, scientifically-sound, statistically-significant research performed by horticulture specialists with Texas Cooperative Extension, part of the Texas A&M University system. This research has proven that EarthKind? roses are among the best flowering cultivars requiring the least amount of care, and that they do the following:

? Give consistently high performance
? Grow in geographically-diverse regions and climatic zones
? Grow in almost any soil type
? Reduce the need for fungicides, pesticides and miticides by 98%
? Reduce the misuse and abuse of commercial fertilizers
? Reduce the need for supplemental watering after the second year by 70%
? Give outstanding performance when integrated in a landscape setting


Utilizing EarthKind? Roses Maximizes Resources

Horticulturists constantly find themselves trying to balance the needs of their gardens with the limited personnel and financial resources available to meet those needs. Utilizing plants which require a minimal amount of human intervention and consume a nominal outlay of a garden's budgetary funds just makes good business sense. For these reasons, EarthKind? roses are perfect candidates for inclusion in public gardens. By incorporating EarthKind? roses in their gardens, horticulturists realize the added benefit of redirecting their precious volunteer efforts and financial resources into areas of their gardens that need greater attention.

The Research

The EarthKind? rose research program is the most exciting development in rose horticulture since the introduction of the first modern rose in the 19th century! It may very well be the largest research program of its kind undertaken in the last 100 years, and is certainly the largest research study that focuses strictly on roses. The goal of the EarthKind? program is for Americans to enjoy beautiful, productive landscapes which require only minimal maintenance while providing maximum protection for the environment. The initial four-year research study included 117 different cultivars (468 total bushes replicated four times in randomized complete blocks). Of the cultivars initially studied, eleven gave spectacular performance despite very adverse growing conditions and an almost complete lack of maintenance throughout the study period. Most of these eleven cultivars, by the way, are limited by cold temperatures to the southern half of the U. S.

In what can only be described as deliberate "rose abuse,? test cultivars were grown in alkaline clay soil with a pH of 8.0. Ideally, roses grow best in slightly acid soils with a pH of 6.5. Test beds contained tight, poorly-aerated clay soil with no soil amendments added at any time during the study period. These roses were NEVER fertilized, NEVER deadheaded, NEVER sprayed with chemical or organic fungicides, pesticides or miticides, and NEVER pruned other than to remove dead wood. Furthermore, these roses received NO SUPPLEMENTAL WATERING during the last three years of the study. The only humane treatment the roses received was the maintenance of a four-inch layer of mulch in the form of raw hardwood chips throughout the research period and the addition of drip irrigation during the first two years of the study.

As one might imagine, the vast majority of cultivars included in the study succumbed to this harsh treatment in short order. The cultivars which remained at the end of the study demonstrated such strong genetics that they were able to sustain high bloom production in spite of the adverse growing conditions. Data from field trials revealed that in all geographic regions where candidates were tested, the initial eleven cultivars reached their maximum mature height, bloom size and bloom production in their third growing season.

The heat and drought tolerance of the cultivars which have received the EarthKind? designation is so strong that, once established, these cultivars flourished in their second growing season without supplemental watering through a 67-day drought with daily temperatures at or exceeding 100°F. The only noticeable effect of heat extremes was a reduction in bloom size in certain cultivars.

All EarthKind? roses should be grown on their own roots and demonstrate tolerance to blackspot. In order to receive the EarthKind? designation, cultivars attacked by blackspot fungus must not drop more than 25% of their leaves more than once a year. Research also revealed that several cultivars demonstrate high resistance to powdery mildew. None of the EarthKind? roses exhibited significant insect problems at any time during the study period.

The first phase of study identified eleven cultivars that produced outstanding results in Southern gardens. These cultivars included ?Sea Foam,? ?Marie Daly,? ?The Fairy,? ?Caldwell Pink,? ?Knock Out?,? ?Else Poulson,? ?Carefree Beauty? (also known as ?Katy Road Pink?), ?Mutabilis,? ?Perle d' Or,? ?Belinda's Dream,? and ?Climbing Pinkie.?

Thanks to the financial support of the Houston Rose Society, funds have been made available to initiate a new four-year study at Texas A & M?s research center in Dallas. The purpose of this expanded study is to identify additional EarthKind? cultivars that grow well in the South as well as cultivars which grow equally well anywhere in the United States. The latter would then be tested nationwide, and the best performers would be included in the first-ever national collection of EarthKind? roses.

National EarthKind? Rose Trials

Texas A & M University horticulture specialists have already identified an initial thirty cultivars for a three-year, nationwide trial that will test the cold hardiness of these selected cultivars. This study will be the ultimate in low maintenance; specifically, it will involve no commercial fertilizer application, no pesticide application, no deadheading, and no pruning. These roses will be watered only as needed, and organic mulch used around them must be replenished once or twice a year. These trials will also include implementation of the EarthKind? soil management program, which features the use of compost and mulch only and completely eliminates the use of commercial fertilizers. A & M specialists recommend mulch made from shredding leaves and limbs of trees native to the area. This valuable material can often be obtained free of charge from tree service companies and makes a long lasting and slow-release fertilizer. Hopefully, the results of this nationwide trial will show a 70% reduction in irrigation, total elimination of pesticides on the plants, total elimination of commercial fertilizers, and a significant reduction in labor and maintenance costs. Participating public/botanical gardens will realize the following benefits:

? The privilege of being an official EarthKind? rose test site and part of one of the most ambitious programs of applied horticultural research ever conducted in the United States
? Including a picture of their trial site on A & M?s EarthKind? Web site
? Grounding in a very pro-active, research-based, easily-understood approach to landscape management
? Recognition as a leader in their geographic area in educating the public about environmentally-responsible landscape management
? The satisfaction of performing strong, scientifically-sound applied field research

Each participating garden will need to construct a new bed in a location that receives at least eight hours of direct sun and good air movement over the foliage. Soil quality of the trial bed does not matter. The minimum number of plants at a given site will be fifteen. Accommodating fifteen plants will require an area of 1,280 square feet and approximately $1,200 to pay for compost, plants, drip system, and mulch. There is no hurry in implementing the trial; it can be started now, the spring of 2006, the fall of 2006, or the spring of 2007. The roses for this nationwide trial will be readily available from several national mail-order rose order nurseries.

EarthKind? Trials in Public Venues

For those who might be skeptical about the EarthKind? program, we invite you to contact Steve Huddleston, senior horticulturist at the Fort Worth Botanic Garden where EarthKind? roses have undergone trial and have been incorporated as an integral part of the rose garden since 2002. Hundreds of ?Knock Out? shrub roses are growing on the ?ramp? in the formal part of the rose garden, bloom April through December, and make quite a showing in this very prominent location. EarthKind? roses can be seen on the Fort Worth Botanic Garden?s Web site at www.fwbg.org (Gardens ? Rose). EarthKind? roses fit perfectly into public gardens because they perform well and look good planted among such companion plants as annuals, perennials, ornamental grasses, and shrubs.

Because the EarthKind? concept flies in the face of the age-old perception that roses are hard-to-grow, field trials conducted by two other organizations are likewise enlightening. The Permian Basin Master Gardeners Association planted a display garden of EarthKind? roses and EarthKind? candidates in 2002. By September 2004, the roses in that garden surpassed even the expectations of horticultural researchers at Texas A&M. These results are truly amazing given the desert-like conditions of this West Texas town. Chlorosis (a result of Odessa's highly saline water) is a common affliction of landscape plants in this area, but it did not seem to affect the EarthKind? roses.

The Houston Rose Society, the first rose society to sponsor an EarthKind? field trial, took a different approach. This group worked with the city of Pasadena, Texas and utilized the asphalt parking lot of a city building to plant a collection of EarthKind? roses. Recently evaluated by researchers at Texas A&M, this field trial certainly tested the extremes of the EarthKind? cultivars. The reflective heat of this asphalt parking lot easily reached 120°F during the summer, yet none of the bushes planted at the site showed evidence of heat stress. The Houston Rose Society test garden is the first field trial to implement the EarthKind? soil management practice of utilizing an organic mulch to sustain plant growth and bloom production. These same types of trials are taking place across the South and are presently under way in New York and Kentucky.

If part of your garden's mission statement is to support research, what better way to fulfill that mission than to be a part of this exciting research project that will help other public gardens expand their resources in a multitude of ways? We invite you to join us in this exciting and historical effort. Without a doubt, the EarthKind? rose program is the future of rose horticulture in the 21st century!

Steve Huddleston, Fort Worth Botanic Garden, and Gaye Hammond, Houston Rose Society, are instructors for Texas A&M's Cooperative Extension Service on the topic of EarthKind? roses. For more information about including EarthKind? roses in your public garden, contact Steve Huddleston at 817/871-7677 or by e-mail at . Gaye Hammond may be contacted by e-mail at or by mail at 8627 Deep Valley, Houston, Texas 77044.

 

Back to Top

Previous Article | Back to Contents | Next Article

Back to Botanical Home

Back to Rose Garden Home