How can I put a wreath on a grave site via a 3rd party.

Some flower shops in Washington DC will do it. But there is a fee to do it

Hi David - It is very common for families and loved ones to hire a florist to deliver flowers or a wreath to a specific grave at the cemetery. Unfortunately, we’re unable to provide any recommendations for florists as they are non-government commercial entities – but there are several within the immediate area who offer this service and are familiar with the property. A quick internet search should find you several options.