Facts in The River Merchant's Wife: A Letter

Text of the Poem 1
"Too deep to clear them away..."   (Text of the Poem)

Moss, unlike ivy, doesn't take root in its substrate or upset that foundation's structural integrity, instead anchoring themselves by way of single-celled rhizoids that cling to surfaces. Clearing it away wouldn't be a terribly difficult process, but would take some time, especially if the moss has grown as thick as the speaker suggests.