There is a fascinating discussion on Chez Vibert Old Roses Forum (many members in deeply drought stricken California) that makes SO MUCH sense....there seems to be a correlation between a rose's height, and the depth of its roots, and subsequent drought tolerance. The 'Mermaid' that consumed my yard was 45 feet long...would have been that tall if trained straight up...roots going down 45 feet would explain it not being affected by the drought at all. 'Seagull', "Barfield White Climber", 'Francois Juranville' all make 20 foot canes...drought has no affect on them. Wild R. laevigata here in Florida can go 60 feet up long needle pines...do the roots go down 60 feet? Indestructible "Pink Cracker Rose" can be a 10-12 foot pillar...roots go down that far? Fortuniana advocates tout as a virtue its roots being a 3 INCH deep mat at the surface...one with a straight face brags that his hundreds of roses on campus (exempt from the restrictions the rest of us have to abide by) ONLY get 7 gallons per bush PER DAY every day! This also makes me think of towering drought tolerant monsters in Denver like "Mr. Nash", 'Seagull', 'Great Western', 'American Pillar', 'Blaze', 'Dr. Van Fleet', 'New Dawn', "Victorian Memory",' Zephirine Drouhin',' Francis E. Lester', 'Lawrence Johnston'. 'Ghislaine de Feligonde' and more that thrive in that very dry climate. I REALLY this we are onto something and will keep it in mind as I breed drought tolerant roses for Florida.