Single Record

PhotoRecords: YES Rich Haswell: Rio Grande, Del Norte, old planted trees and young shoots throughout the town, 20 May 2020

Comments: Early European settlers planted crack willow in Basin towns and farms as a fast grower and a wind break, and the old trees and their young are still found there—Alamosa, Mosca, Bountiful (south of La Jara), Del Norte, Moffat. The one montane occurrence was recorded in 2003 from the South Fork ranger guard station on Alder Creek, prossibly also planted. Salix x fragilis, exotic, is a hybrid between S. alba and S. euxina, and is considered invasive in many parts of the world. Kittel notes that the Salix expert Robert Dorn believes Salix x fragilis has become naturalized and is sexually reproducing and therefore becoming a new species (2023, p. 113). Still, allmost all plants in the Watershed, indeed in Colorado, are female, spreading by vegetative shoots, not by pollen (see Kittel 2023, p. 113). Present in all states of the USA except for those of the Deep South, S. x fragilis can be found in Rio Grande drainage as far south as Big Bend, Texas. Note that slender branches break off from the trunk with a snap (hence "crack willow"), a useful trait in the spread of the plant by shoots, and a useful character in determining the plant. The length of leaf petiole is also a good trait to distinguish S. x fragilis (>10 mm).