I've brewed with whole chamomile flours. 1 hour in the boil. Yes, there is a noticeable flavor and aroma. If you've had chamomile tea, you know it doesn't take much time at all to get the flavor out.
BTW, the whole flowers are easily available at natural food places. Probably cheaper than the dustings you get in the teabags.
Now there's some take delight in the carriages a rolling
and others take delight in the hurling and the bowling
but I take delight in the juice of the barley
and courting pretty fair maids in the morning bright and early