Sacred Fist, Knight of the Rose, Windwalker (3.0), Hexer (3.0, hard entry), Verdant Lord (3.0, druid)
A 63 Addendum Verdant Lord can technically advance non-Druid casting it’s just a pain to qualify for. Also worth noting that command plants and control plants switched names in 3.5 so the entry level is 7 not 13.