Scientific Name
Quercus macrocarpa x gambelii ‘Jack Maze’ ‘Jack Maze Oak’
Jack Maze oak is a hybrid of the Colorado native Gambel oak with the bur oak, which in the recent geologic past, during a wetter climate period, was also widely present in Colorado. As they were both members of the white oak group, where their native ranges once overlapped, they hybridized, as oaks so often do. Long after bur oak retreated from our drying region, its genes persisted in hybrids that remained in the state, especially in canyon bottomlands in the southeastern Colorado counties of Las Animas and Baca. It is also interesting that where the hybrids grow today, pure Gambel oak is not present.
It is not always the case with hybrids, but in this case the foliage shape splits the difference between the parents. It is large and tends to be widest toward the far end like bur oak, but without the coarser lobing and the extremely narrow “waist.” The acorns are larger than those of Gambel oak, but their caps are not fringed like those of bur oak.
The late Jack Maze was a Canadian botanist who did his doctoral research on these hybrids. The ‘Jack Maze’ cultivar was formally introduced into commerce in 2019. The cultivar’s parent, propagated clonally, is derived from a tree in Baca County, Colorado, selected by the late Allan Taylor of Boulder. The tree at Regis was in fact a donation from Dr. Taylor in the first year it was registered. Owing to its origin, the tree is very heat- and drought-tolerant and adapts well to infertile soils. This tree is grafted on swamp white oak, Quercus bicolor, another very adaptable oak species. We believe this tree could grow large, perhaps to 40 feet, but it could also remain much smaller; we have little historical experience to rely on with this tree.