Is rhubarb and asparagus that has been frosted safe to eat?
A light frost will not harm rhubarb. However, if temperatures were cold enough to cause the rhubarb leaves to wilt or become limp then damage has been done. The leaves should be removed and discarded. Any new leaves that appear and are normal can be eaten.
The leaf blade of rhubarb is poisonous regardless of whether it suffered cold damage as it naturally contains oxalic acid. The leaf stalk is the edible portion of this plant. However, when leaves become frozen, the oxalic content of the stalks increases, making them dangerous to consume. Learn more at www.bookstore.ksre.ksu.edu/pubs/ep99.pdf
Asparagus does not contain poisonous substances but frost will cause the spear tips to wilt and give them an off flavor. Remove and discard any spears that show such damage. Learn more at www.bookstore.ksre.ksu.edu/pubs/mf319.pdf
Source: Ward Upham
