They are bolting for seed production now, so the roots are already not very edible. However the flowering display is quite impressive and they will reseed themselves if allowed for both fall and spring germination.

Over here, we plant parsnip seed in late summer, for winter through to spring production.
If you have the space, I'd let at least one plant flower. The insects go crazy for parsnips.
Saving the seed's a bit iffy, since you could be selecting for small, bolty parsnips.
Let fresh parsnip seed hit the ground, and watch its reputation for germination issues go out the window!

I agree, self-sowing parsnip makes a difficult control situation in terms of selection. I find that the seed that germinates in fall (situation is probably different in NZ where ground does not freeze) tends to be very bolty, the ones that germinate in spring less so. Still there is a large amount of bolting, I have to pull most of them. I try to leave only the biggest, of course, to go through the full cycle but it isn't so easy once you have hundreds of em.

Thanks for the replies! Since my vegetable gardening space is limited, I'll be pulling them out. Might just leave ONE---just to see the flower!

Thanks contrms for this thread!
Being a Southern boy, there are a lot of plants we do not
traditionally grown here. No by my family any ways.
Kale, beets & parsnips are a few that I tried last year.
Three parsnips made it up, but only one made it till Spring.
Now I will let it go to seed & see what will happen.
I should put down some compost now, so it will be mixed in the soil by the time the seeds fall.

Parsnips do not like extended hot weather and warm soil, so I suspect most of SC is effectively out of the zone for production of good eating-quality roots.

pnbrown, thanks.
I will let you know if it does anything.
I was told to plant it in Fall or early Spring, so that holds with what I was told.

Just a recollection (that is OT) of one of the original Victory Garden programs which featured two English friends who engaged in an annual parsnip competition. Each planted one parsnip seed in a soil-filled 5' tall chimney flu. Both carefully tended his 'crop' until fall when they extracted the parsnips to measure root length and declare a winner. The program showed that each gardener spent most of a day carefully digging his huge parsnip root, almost one grain of dirt at a time, from the confines of the narrow container protecting the root from breakage. It was a fun program filled with the dedication and humor of British gardeners. How I miss those early Victory Garden programs....

Those english prize-growers are nutty, aren't they? Similar to the prize pumpkin craze in north america. The pumpkin obsession goes back to the early 19th century, I think.