I can't give you any names myself, but I would bet that you could call Producers Cooperative, and they could give you the name of a coastal producer that supplies sprigs or visit their website.
Producers Cooperative Website.
http://www.producerscooperative.com/
They usually have a list of hay producers on their website.
Also you might call the Grimes County Extention Agent, he might be able to tell you of a sprig producer in that area. His name is Rodney Finch, and his number is 936-825-3495
Hope this helps.