There was a William Crabtree who patented 100 acres called "Labour" in Baltimore County on 1 Oct 1718; 100 acres "Crabtree's Lot" in Baltimore County on 20 June 1726, and "Begin" in Baltimore County on 8 July 1730. (Coldham, Settlers in Maryland 1701-1730, p;. 37). There we no Crabtrees in Coldam's earlier volume,, 1679-1700. There was a John Crabtree who immigrated about 1659 in Skordas' book.
William apparently kept acquiring land. He acquired another 100 acres, "Crabtree's Addition" in Baltimore County on 10 June 1734. By then there was also a Thomas Crabtree in the picture, who acquired 100 acres "Minster" on 20 Feb 1733. Both these on p. 50, Coldham, Settlers of Maryland 1731-1750.