Once a gardener decides she wants a certain plant for her garden still another decision has to be made: what cultivar? A combination between \”cultivated\” and \”variety\”, cultivar is a named selection of a species that exhibits an ornamental trait that differs from the straight species (but not too much). An example is Helleborus foetidus ‘Red Silver’ a particularly nice Stinking Hellebore with flowers edged with red.
The Chicago Botanic Garden publishes a research report called Plant Evaluation Notes that reports the results of years of research comparing all of the available cultivars of popular perennial species like Hardy Geraniums and shade-loving Lamium. Most reports look at general garden worthiness, but occasionally they will look at disease susceptibility, like powdery mildew in Phlox or Bee Balm. Typically three issues are published per year. To find current and past issues and ordering information, go to the website of Chicago Botanic Garden.
You can also write Chicago Botanic Garden, Plant Evaluation Program, 1000 Lake Cook Road, Glencoe, IL 60022. Individual issues cost $3.00.
- Top scoring Hardy Geraniums include: Geranium \’Blue Cloud\’, G. \’Brookside\’ and G. macrorrhizum \’Lohfelden\’.
- Top ranking Lamium (Dead Nettle) include: Lamium album \’Friday\’, L. maculatum \’Red Nancy\’ and L. maculatum \’Shell Pink\’.