This species is enigmatic. There is no record of the publication of the name in either the International Plant Names Index (www.ipni.org) or the International Legume Database & Information Service (www.ildis.org), and it is not described in the (currently draft) Flora of China treatment, and yet it appears in the catalogues of several nurseries and botanic gardens. Davis et al. (2002) included it in their study of the evolutionary relationships of Cercis and concluded that it is most closely related to C. chinensis (the DNA used in the study came from a tree in cultivation at the JC Raulston Arboretum at North Carolina State University). The limited information available via the internet suggests that C. gigantea is similar to C. chinensis but has much larger leaves and a more vigorous growth rate. Plants originating from seed collected as C. chinensis during the 1980 Sino-American Botanical Expedition (SABE 1010, from Shennongjia Forest, Duanjiangping, western Hubei) were later identified as C. gigantea by Dr Ted Dudley at the US National Arboretum (R. Olsen, pers. comm. 2007), supporting this supposition of similarity between the two taxa.
An important source of seed of C. gigantea was a large (over 10 m) specimen formerly growing in the redbud collection at the JC Raulston Arboretum, removed in 2001 (probably the same tree as mentioned above). It had a single stem to about 1 m, then several ascending stems, and bore pale pink flowers very early in the season (T. Lasseigne, pers. comm. 2007). It was received as seed from the Shanghai Botanic Garden. Descendants include one accession (NA 65489) at the US National Arboretum (R. Olsen, V. Tyson, pers. comms. 2007), but there are probably many more.