There is an incredible variety of speedwells (Veronica) for a gardener to choose from, with new offerings from breeders every year. How to choose from among all this horticultural largesse? The Chicago Botanic Garden, located in USDA hardiness zone 5, recently released the results of a four to six year evaluation of 61 different species or cultivars of Veronica.
All plants were grown in full sun and well-drained clay-loam soil and were given minimal care in an effort to duplicate the treatment they'd get in most home gardens. The ratings were based on flower production, plant health, growth habit and winter hardiness. The judging was tough. Among the different species or cultivars evaluated, none earned the coveted 5 stars needed to be judged "excellent."
But quite a few received a 4-star "good" and 7 garnered 4? stars. These latter included the hybrid 'Fairytale', with pale pink blossoms; hybrid 'Giles Van Hees', with darker pink flowers; V. austriaca 'Ionian Skies' with pale blue flowers; V. longifolia 'Blue John' with purple-blue blossoms; the V. spicata cultivars 'Baby Doll' with pink flowers and 'Ulster Blue Dwarf' with purple-blue; and V. wormskjoldii, also with purple-blue flowers. All of these plants have an upright growth habit.
The study also evaluated seven cultivars of the stately culver's root (Veronicastrum virginicum), with 'Apollo,' 'Fascination,' 'Lavendelturm' and 'Pink Glow' receiving "good" ratings.
For the complete report on Veronica, go to: Comparative Studies of Veronica and Veronicasturm.