I have a patch of ferns that has been established in my yard for a number of years. In the past week, many of the fern leaves have turned brown and died. Can you help me determine the cause of the die-off and how I might stop this from killing the entire patch? Photo is attached.
Hennepin County Minnesota
The two most likely causes of the ferns turning brown are normal browning or not enough water. Your ferns are under a tree and may not have gotten enough water during the hot dry week. They do best in moist soil. The other possibility is normal browning because of age. The outer fronds die when they are 2-3 years old.
Normal browning of fern fronds usually occurs on the oldest fronds that are closest to the base. When dealing with sunburn, the fronds that are browning are the ones at the top of the plant that are exposed to light. If you shift a brown frond, the ones beneath it are usually nice and green.