Sounds like you are talking about ornamental allium?
They'll probably grow, but may take years to look like the parent plant.

If you mean the small seed that forms on Flower Scapes - they can indeed be planted successfully - as long as fairly fresh. I'd probably leave in cool water - a couple weeks or as long as there is any green at all left in the stem, and then plant in September. They will get consistent moisture to form fall greens after a couple weeks dormancy. Maybe you can plant sooner in your area? Mulch can help with moisture retention, and help keep soil from hardening and limiting growth.

I add a fall layer of leaves, and an occaisional shovel of compost. I also chop and eat the leaves of ornamental allium (use in eggs and stir-fry) when leaves start getting floppy.

If you mean Elephant Garlic seed - you can replant:
any cloves - separated from mature heads, with
all of your onion-like (round) yearlings, and
the shiny hard seed (with one flat side) that forms at the base of most bulbs, and also
the seed from flowering scapes...

It is best to top Scapes right away - or at least a few weeks before harvest. If the flower-head seed of garlic and other allium is open and still really moist - try separating and sprinkling these over a Salad, rice or other dish - it's spicy good and tres' gourmet!

Here is a link that might be useful: