Ken Asmus of Oikos Tree Crops in Michigan purchased seeds of Purple Tree Collards from Project Tree Collard. Five years later, after much observation and selection of his seedlings, he shared clones of “Michigan Tree Collard” with Project Tree Collard. His Michigan Tree Collard plants have been outdoors for the last 5 years in USDA zone 5-6, and have survived temperatures to 0 F. Michigan Tree Collard is a beautiful and vigorous, silver-green tree collard that has purple hues on the stems. Flavor is similar to other tree collard plants.
Ken shared that it may be tolerant of even colder winter temperatures than zero, and even if it appears to have died above ground, it re sprouts from below the soil line once the growing season resumes. Some have hardy enough stems to stay green and sprout slightly above the ground.
In Michigan, his Michigan Tree Collards grow up to 6 feet tall, and if given fertile, well-drained soil with regular water can reach 3-4 feet high in one year. Our California plants are too young to determine a mature height.
Since this is a newly available plant for gardeners, we are unsure how it performs in warm, tropical climates such as Florida and Hawaii. In the last year it has thrived in the SF Bay Area in zone 10A, and Grass Valley, CA in zone 9A.