In mid September (2010) I had the distinct privilege of visiting Darrell Probst's hybrid fields, but I'm not talking about Epimedium here, this time around it was to walk a field of 5000 hybrid Coreopsis seedlings. The seedling field represents 10 years of hybridization efforts in hardy Coreopsis. The key phrase here is hardy Coreopsis, as many of the recent hybrids that have flooded the market, such as 'Sweet Dreams', 'Limerock Ruby', are crosses made with annual C. tinctoria, resulting in plants that are just not reliably hardy in USDA Zone 5. The lack of hardiness and performance on a number of Coreopsis hybrids has left many gardeners jaded (myself included), and wary of trying more because of their unreliability.
In contrast, Darrell searched out and found many our our USA hardy Coreopsis species that were not in cultivation, to add to his hybridization efforts. And of course, he also utilized the familiar Coreopsis rosea (native to Massachusetts), which has been used in Coreopsis breeding before, but remains an exceedingly difficult species with which to make successful interspecific crosses.
Driving to Darrell's field located in western Massachusetts, I tried to imagine what the hybrids would look like, but I was totally unprepared for the astonishing range of hybrids he managed to come up with. Walking the long rows upon rows of amazing hybrids was like being in a living science laboratory, with all of the lessons of botany, genetics, and hybridization just sitting there within the plants looking up at me, it has been a long time since I've been so inspired. Visiting the field was educational in so many ways, here are a few observations:
1. It takes vision, great tenacity, and years of determination to get worthwhile results.
2. It requires gathering and exploring as wide a gene pool as possible, to truly explore the possibilities.
3. It requires LOTS & LOTS of space and thousands of seedlings yearly, to achieve sufficient diversity (and nuances within that diversity), to be able to pick out the best of the best.
4. Incredible effort and expense goes into such seemingly simple endeavors.
Let me take you through a small photographic journey of Darrell's hardy Coreopsis trials. Some of his best groups of hybrids, such as the thread-leaf ones (verticillata group), I'm not at liberty to show (I can assure you they're amazing), but there's lots here to illustrate the process and achievements.