Andy, those warnings actually do indicate āregional rosesā. Personally, I donāt think the one size fits all has ever worked, nor do I believe it is realistic. From the corporate view, they are necessary so keep things simple and streamlined. Economies of scale are well suited to the national dozen, instead of three or four each for five or six regions. Even if the perfect roses for each one could be created, the perverse nature of humans requires they only want what they canāt HAVE.
I also donāt feel it realistic to believe we will ever have national roses which perform similarly across the nation. There are simply too many different climates, different strains of fungi, lengths and intensities of seasons, etc. Even simply considering California, I āenjoyā a variation between day and night temps at the extremes of fifty degrees. The variation between winter and summer in my old climate could be as much as one hundred degrees. The ānormalā annual rainfall is around fifteen inches. This past year, it was FIVE inches. Just a few hundred miles north of me, they receive thirty-five inches with a whopping twenty degrees variation between day and night at the extremes and in bad years, winter to summer variation can be as āgreatā as forty degrees. The kinds of roses which endure my climate are generally going to be rather different from those which flourish in the climate north of me. Even those which are fairly adapted to both, can perform tremendously different between that climate and mine.
Move to Chicago where the annual rainfall is something around forty inches. They sometimes get feet of snow for many months and can have very deep freezes. My climate can dip to the teens in really terrible years, but only for an hour or so before it bounces back to more endurable temps. Add the variation in fungi strains to such tremendously different climates and you get the idea. You know what yours is like in comparison and how popular roses, reported as decent in other climates, perform in yours. Is it honestly realistic to expect any rose to perform to a similary acceptable level in such widely varying conditions?
Can we honestly expect a rose which is programmed to remain evergreen, push new growth and flower well for ten-plus months to know when to shut down and endure the kinds of freezes your area receives? Both of our populations demand the plant remain attractive and endure the extremes in conditions. In this āland of endless summerā it had also better offer at least some color twelve months of the year or it is eventually doomed. We have too many choices which will perform here for the average, unfamiliar ārose buyerā to accept a thorny plant which only flowers a short period. For many, until they gain some experience and learn the benefits, getting them to accept deciduous trees is nearly impossible. A bare plant is dead to them. You can imagine how many have called to report the tree they purchased ādiedā because all the leaves fell off. I always knew to expect it at this time of year. No matter how many explanations were made to prevent it, the calls always came. Youād choke on how many called to report ādead rosesā because the flowers fell off. No joke.
If conditions were more similar across the nation, one size fitting all may work. But even just a few miles here can make tremendous differences. Enough to make whole classes of plants either suitable or totally unsuitable. Right here, Bougainvillea is Kudzu. Three miles away, it freezes to death in winter. Hibiscus is healthy, vigorous, pest free and ever flowering in my yard without intervention. At the bottom of my hill, there is white fly making them require spraying. Travel through the pass just seventeen miles north into the next valley and neither bougainvillea nor hibiscus can be grown as anything other than annuals. Roses are tremendously more adaptable, but you get the idea. I honestly donāt think we can realistically expect the same performance in your climate and mine from the same genetic combinations.