Lamb's ears (Stachys) are popular perennials known for their soft, silver leaves and flower spikes. There are two common groups of Stachys available. The ground cover lamb's ears, such as Stachys byzantina, feature wide, soft, fuzzy leaves and 12-inch-tall, violet-colored flower spikes. The taller species, such as Stachys monieri, are also known as betony. They feature 2-foot-tall spikes of violet-colored flowers that rise above bushy mounds of green leaves.
The Chicago Botanic Garden evaluated 22 types of lamb's ears for ornamental traits, disease and pest resistance, adaptability, and winter hardiness. Based in USDA zone 5, the Chicago Botanic Garden conducted the trial over a six-year period. Among the fuzzy-leaved lamb's ears, the Stachys byzantina 'Big Ears', S. byzantina 'Cotton Boll', S. byzantina 'Silver Carpet', and S. byzantina 'Wave Hill' received the highest scores. Stachys monieri 'Hummelo' received the highest rating of the betony-type lamb's ears. It features dark green leaves and violet-colored flowers that last into August.
For more information about this trial, go to: Chicago Botanic Garden.