QBARS - v35n4 Needed, A More Useful Rating System

by Newton W. Edwards, Alexandria, Virginia

Every 5 years or so our Society puts out a handbook that is looked forward to for the wealth of information it provides, including descriptions and ratings of numerous rhododendrons. As much as the work that went into developing the information is appreciated, many members have expressed the belief from time to time that the national ratings have limited application to their particular part of the country.

In evaluating our rating system we need to keep in mind two questions. Why do we rate plants, and how well do our ratings achieve their purpose? Most of us look to ratings to help us select outstandingly beautiful flowers and plants that will grow well. It's disappointing and costly to lose plants, but even worse, to grow one for some years only to find we are not pleased with it. So, the ratings should be accurate and reliable.

Our present rating system consists of rating three factors. There is a numerical rating for the quality of the flower on a scale of 1 to 5 with 5 the best. There is a similar numerical rating for the quality of the plant considering such things as its branching habit, the characteristics of the leaf, how well it is clothed, and how many seasons it holds its leaf, etc. Finally, there is a rating giving the minimum temperature the plant will normally withstand if it is mature and well hardened. Our Society presently recognizes a single rating for each of the three factors, as assigned by a national rating committee. While it is considered a national rating, it is generally based on the area of the country in which the particular variety grows best. Herein lies many obvious problems.

The Society's present rating committee would like to expand and refine the rating system. It needs to be made more reliable and pertinent and yet kept simple.

The committee is considering recommending that each chapter develop ratings for its specific climate and other environmental factors to best meet the needs of its own members and the gardening public in its area. Different ratings for the same plant in various parts of the country are realistic. It should cause no confusion if the rating organization and its geographical area are clearly identified.

We believe the chapters will take a great interest in developing their ratings for publication as a very worthwhile project. We are all keen on sharing our experience. There are various ways of going about the job. Sometimes it has been done by a committee of the most experienced members, sometimes by a questionnaire to the membership, and at other times by a test garden. The Potomac Valley chapter over the years made unsuccessful sporadic efforts at ratings using each of these methods. Over the past year it has made great progress-in developing its own ratings by a member vote at chapter meetings. The members are enthusiastic, believing it is a significant effort and enjoying the direct participation of sharing their knowledge of flower and plant habit of specific rhododendrons and azaleas. A dozen or so varieties are rated at each meeting in a half hour by a show of hands.

At the beginning of each meeting of the chapter, about 20 minutes is allotted to allow the attending members to rate 12 to 15 hybrids and/or species. Each plant is rated in turn for flower quality (1 to 5), then each for foliage and plant quality (1 to 5), and finally for performance (1 to 5). Members indicate their rating by a show of hands when the number is called. To illustrate, the votes are tallied as:

Anna Rose Whitney 1 2 3 4 5
flower - - 12 16 13
foliage & plant - 2 14 14 11
performance - 16 14 11 -

The results can then be averaged. Thus far, about 50 plants have been rated with surprisingly consistent results.

In addition to urging chapter ratings, the national rating committee is considering the rating of another element of a plant, its performance. By this is meant how good a doer it is - its ease of cultivation, reliability, and vigor. Performance would be given a numerical rating on a scale of 1 to 5 just as is done for the quality of the flower and for the quality of the plant.

At present, we attempt to rate only maximum cold hardiness as a performance factor. We know, however, that the determinants of success are a complex mix of a host of interrelated factors. That is why it is so difficult to say with assurance just why some rhododendrons are better performers. For example, there are patterns of temperature, daily and seasonally, which may be controlling, not just maximum cold. We suspect that the warm nights in the Washington, D.C. area cause a decline in some deciduous azaleas that do better in climates with just as warm days but with cooler nights. There are differences in sun intensities, moisture patterns, different soil structures and chemical contents, different diseases and insects and on and on. It is the genetic ability of a variety to cope with all these stress factors in a particular chapter area that can be lumped together and rated as performance.

The Potomac Valley chapter has made a trial run on rating performance. We are finding that there is a rather close correlation between our ratings given for a plant's quality and for its-performance. If it grows well it is likely to be an attractive plant. This seems to confirm the observation that a rhododendron variety that grows well and is cold hardy is often also able to perform well in handling other stress factors such as heat, drought, etc. However, just rating the lowest temperature a variety can stand does not tell the whole story by any means. For example, 'Jean Marie de Montague', 'Carmen', 'Elizabeth', or 'Blue Diamond', though rated hardy to zero or lower, will not last for long in the heat of the Washington, D.C. area.

The system of rating being suggested for consideration can be illustrated by the following few examples of ratings by the Potomac Valley chapter.

Cultivar Flower Plant Performance Comment
'Anna Rose Whitney' 3.9 2.9 3.2 Lace bugs in sun.
'Belle Heller' 3.4 3.5 3.3 Blooms in fall
'Cadis' 4.1 4.0 4.7 Foolproof
'English Roseum' 2.8 3.8 4.2 Takes full sun
'Jean Marie de Montague' 3.8 2.7 2.6 Declines after few years
'Mrs. Furnival' 4.1 2.9 2.8 Declines after few years
R. impeditum 3.0 3.4 2.1
'Rose Greeley' 4.4 3.8 4.4

The members of the Society's rating committee would like to receive comments on the proposals for having chapter ratings, and on including a performance factor in the ratings. They are: Newton W. Edwards, Chairman Potomac Valley Chapter, Harold Greer, Eugene Chapter, Marge Farwell, San Mateo Chapter, Dr. William Ring, Potomac Valley Chapter, Henry Schannen, Princeton Chapter.