Specifically, a fine texture. The effect of the resulting continuity is this: that the shrubs form a unified backdrop for the plants growing in front of them. I say "backdrop" in the sense that there's nothing jarring in the shrub planting that would draw the eye to this or that shrub. As a result, the viewer's attention tends to gravitate to the flowers growing in the foreground.
Mind you, contrasting textures and similar textures are the extremes, to be saved for "special effects"; in general, you should be striving for a gradual transition between the textures of plant materials. Let a medium-textured plant bridge the gap between a fine-textured plant and a coarse-textured plant.
