We damn the creeping canopy

crawl-clutching its way up walls

as though to devour what we build

given enough damp and hours.

Superstition.

                      Science says it serves

as thermal shield, combating cracks

by warming walls against the rapping

knuckles of winter, cooling them

against the curdle of summer, pulling

at pollutants and purifying air,

answering the perpetual prayer

for a chance to breathe easy.

Blessing or doom, Hedera helix

only works upon what already is:

the ivy guards good walls from salt,

immune to tears and ocean air,

but where towers already waver,

it grows into the cracks and holes,

prying.

          Pulling.

                     Exposing the marrow.