Amorpha fruticosa

History of Spread

Amorpha fruticosa (False Indigo) is native to FL and LA north to WV and PA, west to MI and KS (Gray 1848; Fernald 1950; Stuckey 1990), and in the northern part of the Appalachians to PA (Fernald 1950; Stuckey 1990). A. fruticosa is frequently planted in gardens as an ornamental, and is now widespread. It is generally sporadic inland, but common in coastal regions from VA to ME on the East Coast (Gleason and Cronquist 1991; Stuckey 1990). The earliest reported 'wild' record on the East Coast is from the Hackensack Meadows NJ (Britton 1889).

Amorpha fruticosa is not listed in nineteenth-century floras for the Washington-Baltimore area or in Shreve et al. (1910) for MD. The first report of its wild occurrence in the Chesapeake area was in Potomac Park, Washington DC, 1898 (Hitchcock and Standley 1919). It was considered an occasional garden escape in Washington (Hitchcock and Standley 1919) and MD (Brown and Brown 1972) and the Eastern Shore-DE region (Tatnall 1946).

Harvill et al.'s (1992) map shows occurrences in most VA counties along the Potomac estuary, in several other coastal counties, and in 7 scattered Piedmont and Mountain counties, supporting introduced status in the Coastal Plain and perhaps elsewhere in VA. It was listed by Wass (1972) as occurring on Aquia Creek, a VA Potomac Tributary, and Sipple (1978) reported populations along upper Chesapeake Bay and the Potomac. Krauss et al. (1971) noted occurrences on 'beach trashlines', Kent County MD. A. fruticosa was abundant at North Point State Park, Edgmere MD, north of Baltimore Harbor, and common along mesohaline marshes and beaches at Eastern Neck National Wildlife Refuge , Kent County MD , and at Sandy Point State Park, north of Annapolis ( Fofonoff personal observations 1995-97). Higman (1968) found it to be 'infrequent' on sandy beaches at Ivy Neck, Rhode River, Edgewater MD. In 2003, it was abundant along the shores of Ivy Neck (Fofonoff, personal observations). On the Potomac River it was abundant in Dyke Marsh, Alexandria VA (Fofonoff, personal observations 1996), in oligohaline Brent Marsh, Stafford County VA, Potomac River, (Strong and Kelloff 1994), and common on beach margins at Caledon Natural Area, King George County VA (Simmons et al. 1995).

Amorpha fruticosa has invaded river banks in the Columbia-Snake River system in WA-OR, and is expected to spread throughout the lower elevations of that system (Glad and Halse 1993). It has also been introduced to Greece, China and Africa. (References in Biological Abstracts 1992-1996). This plant has been reported from all the continental United States except MT and NV (Natural Resources Conservation Service 1998).

History References - Britton 1889; Brown and Brown 1972; Glad and Halse 1993; Fernald 1950; Gleason and Cronquist 1991; Gray 1848;Harvill et al. 1992; Higman 1968; Hitchcock and Standley 1919; Robinson and Fernald 1908; Shreve et al. 1910; Simmons et al. 1995; Sipple 1978; Strong and Kelloff 1994; Stuckey 1990; Natural Resources Conservation Service 1998; Wass 1972

Invasion Comments