In February 2018, we planted 3 lines of nursery sword ferns, 12 plants per line, hypothesizing that those planted into Ground Zero (GZN, GZS) would survive, but that those planted into (actually just ahead of) the active die-off zone (ADZ) zone would not do well. All 36 plants have been watered through three summers. The prediction continues to hold:
ADZ: 4/12 ferns dead, 1 marginal, 1 with very slight recover: a few diminutive new fronds
GZS: 0/12 ferns dead, 11 healthy, 1 with 0 fronds last year now has 6
GZN: all 12 ferns are healthy
t.test pvalue, likelihood of this difference occurring by chance: 8.7e-4
GZS: 0/12 ferns dead, 11 healthy, 1 with 0 fronds last year now has 6
GZN: all 12 ferns are healthy
t.test pvalue, likelihood of this difference occurring by chance: 8.7e-4
We surmise that the presumed pathogen no longer resides at Ground Zero - but could possibly return. A continuous dense population of affected sword ferns may be needed for reinfection: the GZ sword ferns may be "socially distant" from current areas of active die-off.
Hello and thank you for writing your findings! This is fascinating but so sad. I was searching the internet for why the ferns in my yard (Spokane, WA) have met their demise after DECADES of healthy life and wonder what is going on. My mom is having the same experience to the north of me a bit with ferns our family has been able to dig up and give some away over the years because they were so plentiful, but now we watch the number of shoots dwindle every year. Any tips would be much appreciated! clskps@gmail.com
ReplyDeleteThanks for this report, though sorry to hear the die-off may have made it to Spokane. I will reply with some details in an email, and ask a few clarifying question.
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