spack install petsc %gcc@5.3.0-spack ^boost+mpi ^hdf5+mpi ^openblas ^openmpi

==> Error: petsc does not depend on openmpi, boost, or hdf5

$ spack info petsc
Package:    petsc
Homepage:   http://www.mcs.anl.gov/petsc/index.html

Safe versions:  
    3.6.3    http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/petsc-3.6.3.tar.gz
    3.5.3    http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/petsc-3.5.3.tar.gz
    3.5.2    http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/petsc-3.5.2.tar.gz
    3.5.1    http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/petsc-3.5.1.tar.gz
    3.4.4    http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/petsc-3.4.4.tar.gz

Variants:
    Name      Default   Description

    boost     on        Activates support for Boost
    double    on        Switches between single and double precision
    hdf5      on        Activates support for HDF5 (only parallel)
    hypre     on        Activates support for Hypre
    metis     on        Activates support for metis and parmetis
    mpi       on        Activates MPI support
    shared    on        Enables the build of shared libraries

Dependencies:
    hypre  hdf5  lapack  blas  metis  mpi  python  boost  parmetis

Virtual packages: 
    None

Description:
     PETSc is a suite of data structures and routines for the scalable
    (parallel) solution of scientific applications modeled by partial
    differential equations.