Plant them early - Like late May or early June.

They like alot of Nitrogen - and will not compete real well with heavy grasses or in Sod. - What I mean is - Its not like you can just scatter them on a field and hope they grow.

I think they really have a place - they attract TONS of bees in the late summer months, provide cover for young Wildfowl - and are a great source of food for your local bird population when they start to dry out.

In my experience - they do very little for deer however. Its a fun plant to put in a plot.