A stretchable buttress assembly is associated with surgical staples deployable into tissue from a surgical stapler having a longitudinal axis. The buttress assembly includes a planar fabric and a bioabsorbable adhesive. The planar fabric also has fibers that are either substantially unaligned with the longitudinal axis of the surgical stapler or substantially aligned with the longitudinal axis of the surgical stapler. The bioabsorbable adhesive is applied to the first side and/or the second side of the planar fabric and is configured to adhere the stretchable buttress assembly to an end effector of the surgical stapler. The buttress assembly is substantially stretchable in one direction. In some versions the buttress assembly is stretchable in a direction parallel to the longitudinal axis. In some versions the buttress assembly is stretchable in a direction perpendicular to the longitudinal axis.