They are self-sowing and pollinated by bees aggressively.

Does toadflax reseed?

Slender spikes of tiny violet-blue snapdragon-like flowers over narrow, whorled, blue-grey leaves light up many an old garden. Blooms all Summer in full sun or part shade. Fairly drought tolerant once established and it reseeds!

How do you collect toadflax seeds?

Crushing a round seed pod from a petunia or toadflax plant releases dozens of tiny seeds. Marigolds (Tagetes) leave behind papery sheaths filled with what seems at first to be fine dried straw, until you pull the sheath away and see the dark seed at the base of each shaft. Some flowers produce larger seeds.