The plants or shrubs have not been trimmed and are overgrown.
The backyard is shrubby, overgrown, and unkempt.
The fact that the plants or shrubs have not been kept up doesn't mean that is a backyard.
exists s1 x1 x2.((n_plant(x2) | n_shrub(x2)) & (n_plant(x1) | n_shrub(x1)) & Theme(s1,x2) & a_overgrown(s1) & -exists e1.(Theme(e1,x1) & v_trim(e1)))
exists s1 s2 s3 x1.(n_backyard(x1) & Theme(s3,x1) & a_unkempt(s3) & Theme(s2,x1) & a_overgrown(s2) & Theme(s1,x1) & a_shrubby(s1))