Why not take advantage of azaleas' spread and cover a shady slope with them? While some of us have – at least on paper – crossed out the big old-timey shrubs in favor of their new diminutive forms, we may have also forgotten how valuable some of these bulky plants can be. Here, Japanese kerria (Kerria japonica) produces its bright-yellow flower clusters in mid-spring. Most of the species grow three to six feet high and a little wider. Will tolerate any soil as long as it's well-drained.