Baltisk Rod Purpurkal kale originated in Siberia prior to 1885 and is considered an heirloom variety. This kale is very tender and has ruffled curly leaves that are dark green to purple. Beautiful kale. This also very ornamental kale can grow to 2-3 feet tall and has a mild, sweet flavor. It can be grown as a spring and early fall crop. Biennial, perennial zones 7-10, in colder climates their leaves may die back, but their root systems will remain alive.