How did the Vitex negundo ruins pile form?

Cymes arranged in panicles, terminal, 10-27 cm long, peduncle densely covered with gray-white fluff; Calyx bell-shaped, with 5-lobed teeth at the top and gray hairs outside; Corolla lavender, puberulent outside, 5-lobed at the top, 2-lipped; Stamens extend out of corolla tube; Ovary subglabrous.