Answer: The tree ferns that thrive in California include Blechnum, Cyathea cooperi, and Dicksonia. Blechnum is a dwarf tree fern, reaching only 4' at maturity. Dicksonia antarctica, the Tasmanian tree fern, is the hardiest of tree ferns. The thick, red-brown, fuzzy trunk grows slowly to 15'. It has many arching, 3-6' fronds, and they are more finely cut than those of Australian tree fern (Cyathea). The most commonly grown tree fern is Cyathea. It eventually reaches 20' tall and 12' wide. The broad, bright green, finely cut fronds have brownish hairs on the leafstalks and undersurfaces. Hope the above information helps you identify your tree ferns; I can't estimate their value but a local landscape contractor might know their worth.
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