Solidago gigantea

This is Solidago gigantea in the broad sense accepted by Kartesz (1994, 1999) which includes plants across the U.S. and Canada. FNA (vol. 20, 2006) recognizes a more narrow treatment which does not include western populations.

Solidago gigantea is a perennial forb occurring in a wide array of moist habitat types, including floodplains, ditches, open woods, thickets, and moist depressions in grasslands of North America, from British Columbia east to Nova Scotia, Canada, south through the Florida Panhandle, Texas, and Colorado in the United States, and Mexico. It is also introduced to Europe and Asia. There are over 300 estimate occurrences of this species in its native range, which are potentially threatened by development, rights-of-way construction and maintenance, invasive species, alteration of hydrology, and other threats in some places. Little is known about threats and trends, but with a large range extent, large number of occurrences, abundant habitat, and broad habitat preferences, Solidago gigantea is considered secure.

The native range of Solidago gigantea occurs in North America, from British Columbia east to Nova Scotia, Canada, south through the Florida Panhandle, Texas, and Colorado in the United States (FNA 2006, Weakley and the Southeastern Flora Team 2025), and Mexico (Villasenor 2016). It is also introduced to Europe and Asia (POWO 2025). According to the Flora of North America Editorial Committee (2006), "reports of hexaploids in the mountains from Alberta, Idaho, Oregon, Washington, and northwestern Wyoming all have minute stipitate glands on the phyllaries, peduncle bracts, and sometimes the distalmost leaves; such plants belong in S. lepida, as do plants from British Columbia." However, Semple (2025) noted that "work done since FNA revealed that S. gigantea can be sometimes somewhat glandular in the inflorescence making it harder to separate from S. lepida," and includes disjunct populations in British Columbia, Washington, and Idaho in the range map for the species. The native range extent was estimated to be over 4 million square kilometers using herbarium specimens and photo-based observations collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025).

Based on herbarium records, photo-based observations documented between 1994 and 2025, and anecdotal evidence, there are more than 300 occurrences in the native range (GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025).

Although threats are not widely documented, Solidago gigantea is potentially threatened by development, rights-of-way construction and maintenance, invasive species, alteration of hydrology, and other threats in some places. However, their overall impact is likely negligible given the species' broad range, large number of occurrences, tolerance of light disturbance, and affinity for typically abundant habitats.