Tree Fern tests in Winter 2006

During Winter 2006 I selected the following ferns for frond damage testing:

• Dicksonia Antarctica – Outside with straw stuffed on the crown.
• Dicksonia Fibrosa - Outside with straw stuffed on the crown.
• Dicksonia Squarrosa – Unheated greenhouse with no protection.
• Cyathea Cooperi - Unheated greenhouse with no protection.
• Cyathea Medullaris - Unheated greenhouse with no protection.
• Cyathea Australis - Unheated greenhouse with no protection.
  

That Winter had a max outside of -8c and inside greenhouse temp of -4c. Here is what happened:

• Dicksonia Antarctica – Unrooted specimens lost their fronds at -7c. Rooted specimens had some damage but no loss.
• Dicksonia Fibrosa – No damage to fronds at all !!!
• Dicksonia Squarrosa – Upper fronds browned off and lower fronds were OK.
• Cyathea Cooperi – All fronds browned off.
• Cyathea Medullaris – No damage to any fronds.
• Cyathea Australis – No damage to any fronds.

D. Fibrosa therefore won out with no damage to the fronds at all !!!! I was surprised by this. I was also surprises that the C. Medullaris had no frond damage at -4c. It is supposed to be a weakling, like the C. Cooperi.