To make the dia. of opening variable to attain a special good looking by forming a plurality of pleates of bellows shape in the longitudinal direction on a cylindrical side surface of a flowerpot cover molded of flexible synthetic resin, and a bent and outward developped part with a slant bending line in each pleat at an upper end of a side surface part.

A flowerpot cover obtained by blow molding flexible synthetic resin has as its cylindrical side surface 1 a plurality of bellows-shaped pleates 1a... bent along longitudinal lines 2 at equal intervals and a developped part 3 formed by being bent along a slant line 4 for each pleat 1a, along the whole circumference of an upper end of the surface 1. A bottom surface of this cylindrical body is closed with a bottom board 5 to prevent leakage of water. In the application, the opening degree of each pleat 1a... is changed with the elasticity of the flexible synthetic resin to have a required dia. of the opening part.