Further Thoughts on a Rating System For Rhododendrons
Edward H. Long, Oakland, Calif.
An article in the October 1962 Quarterly Bulletin, presented for discussion the possibility of establishing, first a special up-rating system for cold areas (H1 & H2) and second, several geographical areas based on climatic conditions, to allow a more satisfying and in some cases a more exact index of local plant performance.
The article cited as an example two cases of plants growing in H1 and H2 areas and now rated 1/2 and 2/2 that might be placed in a special geographic area and arbitrarily rated 4/2. The proposal to create geographic areas based on climate has much to recommend it but the idea of changing the rating system to up-grade low rated plants could lead us into difficulties. If this were done it would necessitate a relative adjustment of the present flower rating of the (three) and (four) rated plants now growing in H1 and H2 areas. "Rhododendrons In Your Garden" shows in the Variety Group, four plants with "4" rated flowers and three plants with "3" rated flowers now growing in H1 and H2 regions. We have a similar situation with a number of species and azaleas with a number of plants with three and four rated flowers growing in cold areas.
This illustrates the complications we would encounter if we amended our standard rating practices to provide selective artificial upgrading in areas where climatic conditions prohibit the growing of many choice high rated species and varieties.
We have at present several unsatisfactory rating problems in California brought about by climatic conditions which should be reviewed.
We have a few plants that perform above the book figures but are under rated because they were evaluated in an area where they do not grow their best, the Pacific Northwest. If we follow the established practice of rating, a plant where it does its best we should up grade such plants as R. 'Broughtonii Aureum' from 2/1 to 4/2, R. 'Countess of Haddington' from 2/2 to 3/2, R. 'Goldsworth Crimson' from 1/1 to 3/2, R. 'Unknown Warrior' from 1/0 to 3/1 and several others.
The weather is too warm in California to allow complete winter dormancy. The plants so effected are quick to respond to a rise in winter temperature of 70 or 80 degrees. This gives premature blooming with small distorted flowers. With some plants the flower buds develop to a point where the following February frosts kill the buds. Some examples of this are: R. 'A. Bedford,' 'Lady Montagu' and also 'Elizabeth' that blooms all winter.
There is a sizeable list of highly rated plants that do not grow well here and the fatality rate is high.
The cause of our troubles seems to stem from our effort to grow plants under weather conditions which inhibit the plants normal seasonal functioning. We can liken it to the effect of climate on commercial fruit trees. You can not grow apples, peaches, or apricots where there is no frost and the plants do not get their normal winter "rest period." You cannot grow oranges in the tropics commercially where it is too warm as the trees bear little fruit.
My observations indicate that difficulties in plant culture in the Northern California Area are more often found with the plant groups carrying H1, H2 and H3 hardiness ratings. These being species or varieties whose progenitors came from high altitudes or cold climates.
The complications involved in applying a uniform rating scale over a wide geographic range are numerous and substantial and suggest that this subject should be approached with caution and a better understanding of varying climatic conditions not widely understood when the present rating system was established.
To accomplish a better understanding of our rating change needs, we are now engaged in a survey by all members of flower and bush ratings. These figures will be forwarded to Chairman Cecil Smith when completed. The completion of this survey may produce results that will help us in arriving at a decision as to the need of a further look at our rating system. Rating systems can not do the impossible and if made too complicated will not be widely used.
The Hardiness Ratings take care of the cold weather conditions but do not help in climates as ours. It would appear best in our case to list the plants that do not respond satisfactorily to our climate and make this available to those interested.
This is written with the understanding that there are small areas in Northern California, generally close to the ocean and at elevations of 700 feet and over, where the conditions cited above do not prevail. Such conditions which exist within a mile or so of unsatisfactory growing conditions would prohibit the use of area maps.