It works good as a base layer, or if there is a bit of rye or wheat in a cut corn field. But I would suggest always trying to use what you find in that specific field. Don't be afraid to take all of your killer weed off your blind if, for some reason, it doesn't match your field. If your blind is wet and the field is dry (or vise versa) you can have problems, or if there is a heavy frost. Key is to match your field the best you can.
This would be less important on a boat, but still try to match. Killer weed can be a good start, but is typically not enough to blend with your background, due to the fact that is always changing. I store bags of different color killer weed in my trailer to try to adapt.
Hope this helps,
Neil