In message , Rachel Sullivan
writes
Plant it well & add a pipe going down to the roots (fill it with
stones) so you can pour water straight down to where it's needed.

No doubt para 4 in the Planting directions help Barkers sell more
clematis plants :-)

Unless you plant with a little of the brown section at the bottom of the
stem above ground, you can get disease or rot. Also cut the bottom out
of a 3" or 4" pot and place upside down to keep the sun away from the
roots.

--
Tony Morgan