In article wildbilly-253140.17293324062009@c-61-68-245-
199.per.connect.net.au, says...

Then you have a different flower. My come up out of uncultivated clay
and lives lone enough to seed for the following year. I have taken to
watering mine when I think of it, because they are free beauty, along
with the red valerians, fox gloves, and the nasturtiums, but they endured
a decade of neglect, when we first moved into this house.

From the Valerian we planted a few years ago, only two plants of eight
survived neglect. (Valeriana officinalis Anthos) Valerian and our
variety are listed as hardy from zone 4 to 9.

And it might be our variety, but in the riot of plants we have growing,
they don't seed at all.

Zone 5... sandy soil.