A quick fix for an awkward size plastic pot

quality paper cut to form a tube to fit snugly around the plastic pot (if you want to taper the tube see glass lampshade post from this time last year for cutting angles)

drop tube over plastic so it can be removed for watering but doesn’t gape

cut strips of contrast paper and concertina them before sticking the folds to the top of the tube, I overlapped three strips to get all the way round and used quick grabbing liquid glue so I only had to hold the concertina strip in place for a few seconds

a final strip was cut in half lengthways with decorative scissors and taped to the bottom of the pot